Kurl-On — kurlon-sagging issues in mattress

I bought 3 (Size - 72*35*4, qty - 2 and size - 72*48*4, qty-1) kurl-on mattresses on 12.02.2015 from the handloom emporium, vikas marg, shakarpur, delhi-92. After 7 month or so on, the mattress size-72*48*4 among them depressed in centre. Due to unawareness, i have not been complained before. So, please direct ur care person at my location to examine the mattresses and solve the problem.
Now the mattresses became un even and not suitable for use.
Biggest brand kurl-on company why manufacturing such worst product. My request is pl exchange the bed immediately.
My address:
Mr. Alam,
Cr-215/5, lalita park, laxminagar,
Delhi-92
My mobile no - [protected], [protected]