Documentation outstanding for 4 months

We bought a car from Smith Luc. Actually a great car that does not give any problems. We got in-house financing and paid the last premium end of January 2018. Never skipped a payment. We went to the office and the contract was marked "fully paid". We were handed the green vehicle registration papers. The friendly lady at reception then noticed that they did not have a copy of the previous owner's ID. Smith Luc promissed to e-mail it the next Monday (we went there over the weekend). Monday came and went. Both me and my husband phoned them numerous times and only got empty promisess that the ID will be e-mailed the next day. Later we were told that we must speak to Smith directly, but he was never available. It is now 16 April 2018. We still have not received the ID document. The car is not registered and the license disk expired at the end of December 2018. The problem is that I can't drive the car and I can't register the car on my name. The registration is getting further behind every month and I will have to pay for it. I see there was a similar post about them. Please think twice if you want to buy from them.