There she goes again... blathering on when she should just shut up.

I suggest you contact the better business bureau in your town and theirs. Send the company a copy of your letters.

Clearly there are other factors, including the labor being incorrectly done, that could affect the life of the product. THAT is why they do not go further than the value of the part. Read the fine print. Deal with reputable first rate product sellers and installers and you should not have this kind of problem.