Dealer wants me to pay more after I signed the paper work and took delivery of the vehicle.

So what should I do in this case?What happened: negotiated on a 2019 Ducati Monster 821 otd price $11,800.00 over the phone a few days later went into said dealership but the sales manager I was working with wasn't in ended up working with the finance manager to finalize the deal.The monthly payment I was to pay and the cost of the bike was significantly lower than the otd price I was quoted on the phone. The finance manager said that in their system they were going off of the VIN for a 1200 S not the 821 so I happily signed all the documents took the bike home and yesterday I get a call from the Sales manager that saying they sold the bike at the wrong price and that they can't send the paperwork to the finance company unless they fix the issue.What should I do? via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/fl6xyi/dealer_wants_me_to_pay_more_after_i_signed_the/?utm_source=ifttt