fixed fee appointment with a solicitor, followed by one letter from them, and also make sure it's forwarded to both parties, and to trading standards .... then see what happens.
I am also slightly lost by the "This product was not purchased from our company" bit, i must have missed something somewhere.
Either way they are hoping for the "i've had enough do whatever you want" reply, in other words whatever costs them nothing, and honours none of the initial fit for purcahse sale
well i havea reply for them..... under no circumstances will i be dealing with them... that was watercoolinguk.com right ?