Nothing you can buy or do on your own (quick and cheap) will bond soft vinyl of any kind since there are too many oils involved in the plastic itself which restrict adhesion.
If you bought it at West Marine
it's almost suredly a Taylor fender...chances are that if it is one of their's if you call them and remark how much you like their product they will replace it.....you'll probably have to pay shipping
....but they are a great company ( customer service
Your best bet is to just buy a new one because the 120.00 you spend on a fender you will save in peace of mind when it comes to every odd noise
you hear coming from your boat
in the general direction of that fender.