Anyone have experience with returning a mattress?

I’m interested in purchasing one of the Sleep Science mattress/base combos. The problem is that they have none in store to lay down on and try out. Same with all local mattress stores, they don’t sell them.

I’m wondering if I buy it and don’t like it, what is the return process like? I wouldn’t be able to bring it back to the store myself. Would they come pick it up? If so, is there a fee?

Thanks