You were dealing through the Business Section, which assumes that you have a basic understanding of the ways of the world.
You appear to have signed a Rental Agreement with "Rent Smart" which was for a specific period of time.
Did you read that agreement.
Most of us would understand that "Rent Smart", buy the piece of Equipment from the Seller and then Rent it to you. Making their profit from the difference in the in the cost to them and what you contracted to pay them over the fixed period of time.
Which part of that do you not understand?
Did you perhaps expect them to perform this service for free?
I'm sorry but I cannot muster a great deal of sympathy for you as, had you done even a modicum of research, you would have understood what was involved.