Kurl-On — Strain on mattress and the dealer put bill 18000 which is above the price mentioned in the mattress pack

Sir,
Today I purchased kurlon convenio mattress. In the mattress the price sticker is mentioned as 15742. But the dealer put bill as 18000. Why your dealer is cheating customer like this?
And the mattress is full of yellow strain. I asked regarding this to the dealer they says it’s model. I need to know about yellow straining my mattress. Am using kurlon product for many years and my brother recently bought kurlon spine therapy mattress. In this case this type of issues looks horrible. So please do the needful to me. And here I attach the yellow strain with this mail. I request again and do the needful for me