Poor after sales experience

I recently purchased a vehicle from We Buy Cars from their online auction. The sale itself went off well, but the after sale service is terrible. I was bombarded WhatsApp messages and an email stating that the registration documents are available for collection. I contacted the Midstream branch to inform them that since I am based in Cape Town, the documents will have to be couriered to my nearest Postnet. This I arranged via their Customer Service line. It has been 2 weeks now without a response to my request, nor a reply to my emails.