I have had an AIM bag for about 5 years I think and it gets some stick often overweighted n the range with 100 plus rounds in mags and the rifle and other bits when being used on a range... no issues at all.
However I feel that you may be being a bit unfair to the company.
I understand that your bags is nice and clean and looks like new BUT does that alter the number of times that you have opened the zip?
The company gives a 2 year warrantee on its product..... you are 1 year over that. where do you expect the cut off time to be when they say 2 years?
Yes it is only the zip, but often they have to almost remake the product in order to replace. a zip.... almost cheaper to just replace the thing!
I know that it what Napier did as I used to buy their returns at the Midland Game Fair and get stitching redone at my local proper cobblers for 3 quid a bag!
I respect to where the bag was made, it was the zip that failed, where was that made?