Sony India — Mp3 player (Nwz-w273sbm1e)

I have a complaint against a Sony product i bought in 2013. It was sony water proof mp3 player(NWZ-W273SBM1E) from e bay. Ever since, i have been getting it replaced every 6 months due to faulty charging cord. It also remains undetected on computer. Pls find attached warranty. When i asked for my money back after endless trips to Sony service station, the exec told me that there would be no reimbursement and that the product could be replaced with a new one. It has already been replaced twice and now the third time, I have exhausted my warranty by a few days (its valid till November 2015 only). I am told that the product could be repaired changing lower that usual fee (and that too is not confirmed). My question is: why should I pay to get repaired a faulty designed product? How can the same issue arise thrice? Why doesn’t the company admit that there is a design issue and discontinue the product instead of selling it to gullible customers? Why am I not being refunded for a product I hardly used?