Can I be accused of stealing a U-Haul truck for non-payment but I have a receipt signed by the clerk saying I paid?

I rented a U-Haul truck. I was given a receipt stating the truck was paid for but the clerk never asked me for any money since I was in a hurry. I wasn't thinking about it either. I left and 8 hours later and being accused of stealing a U-Haul truck. They repo the truck and now I'm being asked to go for questioning from the state police.