Renewal

I currently have Norton 360 which is due for renewal in 7 days. The online renewal price was too high so I purchased what I thought was a key for renewal. I have discovered that the key I have bought is not the right version for full renewal as it does not include backup. I can back up separately and intend to use the non backup key I have to renew but am not sure how that will leave things or even if it will work. I did speak to someone at Norton a couple of weeks ago who offered my a much more reasonable renewal cost but this was after I had purchased the new non backup key.

With thanks in advance can anyone let me know what will occur if I attempt to renew with non backup key?