I don't think you have any redress against the retailer as he seems to have upheld his end of the bargain with you in his effort to "make you whole" again. I'd tend to agree with the retailer on this one. It's a warranty issue with the manufacturere of the sail covers. So it would seem that you need to get a copy of the written warranty policy of both the retailer that sold you the covers, as well as the sail cover
manufacturer. Usually, the retailer will have a warranty stipulation that reads along the lines of "warranty issues are the responsibility of the manufacturer" so as to take itself out of the loop. If that is the case with this retailer (very likely) then you've likely reached the end of the road with them. Next up is the written warranty from the manufacturer. Their warranty will likely read along the lines of "they'll repair, or replace, their product due to poor workmanship - at their discretion" . If their warranty expressly states that "They are not responsible for damage caused by installation
, or misuse" - then the case against them becomes a bit more difficult since it'll boil down to your word against theirs.
If it were me I'd get on the phone
to the president of the cover manufacturers and start off a genuine conversation re: his partial responsibility in your eyes. I'd express that I understood that there would unlikely be full compensation for the sails
forthcoming (which you must admit is fair since the sails
of still of practical use, but just aesthetically displeasing) and try to get him to meet ya half way. If I were able to get half the money
back - I'd consider it a wash. As you've already surmised - the cost of trying to prove negligence on the part of the manufacture would be prohibitive at the dollar amts we're talking about. Since that is the case, the best you can realistically hope for is a partial compensation. Of course you could threaten to drag their name through the mud, and it might yield the intended result. But ultimately what happens with that is the manufacturer gets together with his lawyers and has a new warranty drawn up that provides ALL future customers even less redress than exists currently - so in the end we all lose out (including you in the future).
Just my 7 cents.....