I am very sorry to hear of your troubles, but I have some advice that could help, maybe.

I would seriously consider legal action, specifically with regard to" fitness for purpose" and / or "merchantablity". If they don't explicitly advise their customers to re-clean the head cover, they are open to signifcant liability.

Find a lawyer that would agree to a percentage of the settlement as compensation (a good motivator for lawyers to work efficiently) and go after these dolts.

My 2.3˘