Extremely poor customer and after sales service!!!

We purchased a vehicle from webuycars midstream in good faith 3months ago. The sales person was very unprofessional throughout the purchasing process and after. A service was supposedly done on the vehicle and certain parts replaced before we took receipt it, was paid for but we never ever received any invoices to date nor proof as to what was done and what parts were used as we were told by the sales person that original parts were to be used as the vehicle was of a newer model. Even after numerous attempts made requesting invoices, involving the same sales person, the customer service department and the Branch Manager, we were just ignored and treated like imbeciles. What was said was not what was done and somewhere something is being covered up in my opinion. The turbo of the vehicle has since packed up and the invoice is needed for vehicle warranty claim submission, which we are not in possession of and are now stuck. Paying for a vehicle which is not driving.