Baytown GMC Buick

We purchased a Tahoe from a sales person by the name of Richard. He was very helpful at the time. There was a seatbelt cover missing and he said he would mail it to us. It's been nearly 2 months and we still don't have the cover. We never recieve the plates for our vehicle either. The car has been registered in the system and still no plates? We've left many messages for Richard and have yet to hear back from him. We get his voicemail every time we call. I finally called and asked for a manager and he couldn't even find any paperwork on our purchase and asked if he could call me back. Still waiting......