Just thought I'd share a very positive Symantec Customer Support experience over here :-)
I was having problems with my internet connection - it was dropping all the time. My NIS 2010 subscription was due to expire in 5 days, but I renewed it with a new product key in case the internet connection collapsed altogether during the next days - which would obviously result in my not being able to renew NIS and in the deactivation of the product.
Fortunately, the internet problem disappeared (at least it has done so for the time being), and I nipped round to Customer Support to ask if it was possible to add back the 5 days from the old subscription.
The support agent was extremely polite and efficient - and gave me 30 days extra!!! 
A big thank you to Anjith Raju for helping me with my subscription chaos 