YOU said the numbers don't match.
Where do you think the VIN number is located and where did you look for the VIN number?
Did you just rely on the sticker that typically located on the fiberglass body at the lower left front of the trailer?
The CT13's I have owned have had the actual VIN stamped in a metal plate under the trailer in the middle on one of the chassis cross spars. Very easy to see if you know where to look.
I have also seen the VIN stamped in the frame in front of the propane
tank holder. May be covered by paint
however a little scrapping and you should find if located there.
camper trailers where built in 5 different plants by different vendors contracted to Uhaul
I suggest you personally again go look to make SURE the that you are looking at the correct VIN number (Not the Uhaul inventory number) before you go and start calling the cops and raining on the seller's parade.