Dear Sir
I am writing to request an exchange for the wristwatch (model no.) which I bought on (date) from your store for (amount). Unfortunately, the model your salesman, (name) sold me is not waterproof, although I had clearly explained to him that my hobby as a scuba diver requires me to wear a waterproof watch.
I discovered the problem when the watch stopped while I was bathing my child the following day. Although I returned to the store on (date) for a refund, (name) insisted the watch was waterproof and refused my request for a refund.
I am, hereby enclosing a copy of my receipt and warranty. Kindly inform me at my (phone no.) with an appropriate solution to my problem.
Sincerely,