Simply rest They do not want to refund 100% of the purchase price of the bed I am returning due to faulty air mattress . Tempe, Arizona

I purchased the top of the line air mattress from simply rest and it never held air. After numerous attempts of trying to resolve the issues with the product, which never came through, we wanted to return the product for the refund we were promised at time of purchase.
Now that we want to return it, they do not want to refund all of my money spent on the mattress.
They told us when we bought it there was a no hassle refund.
And when I was ordering the mattress Joe, the supervisor, told me if I placed the order right now he would throw in the platform. Now that it's being returned they want to charge me for the platform and refund me for $400 less than what I paid.
To top it all off they became completely arrogant and unprofessional.