Why Automatic renewal

Norton provides subscription terms on product page...your location:  for example:  

*Important Subscription, Pricing and Offer Details:

• Your subscription begins when your purchase is completed (or otherwise, when your payment is received). You must download and install on each device, or complete enrollment to get protection. Special offer(s) may expire at any time at NortonLifeLock's discretion.
• By subscribing, you are purchasing a recurring subscription which will automatically renew.
• The price quoted today is valid for the offered introductory term. After that, your subscription will be billed at the applicable monthly or annual renewal price here. The price is subject to change, but we will always send you a notification email in advance.
• You can cancel your subscription here, or by contacting Member Services & Support at 844-488-4540. For more details, please visit the Refund Policy.
• Your subscription may include product, service and/or protection updates and features that may be added, modified or removed subject to the acceptance of the License and Services Agreement.
• The number of supported devices allowed under your plan are primarily for personal or household use only. Not for commercial use. If you have issues adding a device, please contact Member Services & Support.

• Virus Protection Promise: To be eligible, you must have a qualifying subscription that is automatically renewing. If a Norton expert is unable to remove the virus from your device, then you may receive a refund based on the actual price paid for the current term of your qualifying subscription. If you have a bundle (a qualifying subscription from NortonLifeLock purchased with either another offering from NortonLifeLock, or a third party offering), your refund will be limited to the Manufacturer’s Suggested Retail Price of only your qualifying subscription for the current term, not to exceed the total bundled price paid. Any refund will be net of any discounts or refunds received and less any shipping, handling and applicable taxes, except in certain states and countries where shipping, handling and taxes are refundable. The refund does not apply to any damages incurred as a result of viruses. See norton.com/virus-protection-promise for complete details.

https://us.norton.com/products/norton-360-deluxe

*Important Subscription, Pricing and Offer Details:

• Contract Type: contract for an annual subscription, starting when the transaction is complete. Click here for our Terms of Sale.
• Set-up: to get the protection/service started, you must download and install on each device and/or complete set-up.
• Free Trial: payment method required if signing up for a free trial (credit/debit card or PayPal only). When the trial ends, the paid subscription starts and the first year is charged, unless cancelled before. Special offer(s) may expire.
• Renewal Cycle: automatically renews each year after the initial term, unless the subscription renewal is cancelled before the day you are due to be charged in your account or by contacting us. Click here to learn how. 
• Renewal Prices: may be higher than the price for the initial term and are subject to change. They are charged up to 35 days before the subscription is due to renew and we send you a notification email with the renewal price before.
• Cancellation & Refund: you can cancel your contract and request a full refund within 60 days of purchase. For each annual renewal or free trial, you can request a full refund within 60 days of being charged, and after the 60 days, a pro-rated refund of the days left in your renewed subscription term, beginning the month after you request the refund. For details, visit our Cancellation & Refund Policy. To cancel your contract or request a refund, click here.
• Updates: your subscription may include product, service and/or protection updates, and features that may be added, modified, or removed, subject to the acceptance of the License & Services Agreement.
• Usage: for non-commercial household use only. If you have issues adding a device, please contact us. 

2 Virus Protection Promise: You must have an automatically renewing device security subscription with antivirus for the virus removal service. If we are unable to remove the virus from your device, you will be entitled to a refund based on the actual price paid for the current term of your subscription. If you have a subscription from NortonLifeLock purchased with either another offering from NortonLifeLock or a third party offering, your refund will be limited to the price of only your subscription for the current term, not to exceed the total price paid. Any refund will be net of any discounts or refunds received and less any applicable taxes, except in certain states and countries where taxes are refundable. The refund does not apply to any damages incurred as a result of viruses. See Norton.com/virus-protection-promise for complete details.

https://uk.norton.com/products/norton-360-deluxe

I have similar problem!  WHY am I asked to renew my credit card details in order to make it easy for Norton to take an unspecified amount of money to renew my contract. Either I choose to stay with a very good Anti Virus Plus cover at a price I can afford or I cancel the contract. My credit card has expired and I will not be replacing it with my new one.  I would have preferred to talk to an human being but that is difficult these days!  If Norton whishes' to contact me, they have my details but I guess I will have to put up with daily on-screen warnings.  Most annoying.