Bad service Team Merbeda

I bought a vehicle from a 75 year old man. He bought a engine from Merbeda in 2010 and didn't know he had to go for Police Clearance. He bought the engine from Merbeda but lost the slip. I went to them to enquire and the send me up and down for info from buyer of engine. They said they will check the engine number and find out if its theirs. They never did and I went to find out about it and send the proof. It was their engine and it was bought from them. Now I'm told stories about waiting for the lady in the office to write a slip. They are rude to me and starting to ignore me when I ask for the slip. The one guy blocked me on WhatsApp today after I asked him if the slip is ready to collect.