Sleep Number review: denying refund on bed frame

Sleep number bed purchased 1/25/2020 at Rapid
city SD, sleep number store. ph. [protected]. Flex fit adjustable bed. Salesperson Derek Dumbie said if not satisfied in 100 days bed could be returned for refund. So when called to return bed on 3/20/2020 was told that bed frame base could not be refunded as was adjustable frame. This was not revealed at time of purchase. Why would anyone want to to trial on sleep number bed if only half of bed could be returned? I do Understand that the delivery fee and linens are non-refundable.