Poor service from AST Motorcycles Mossel Bay

After sending my scooter to AST Motorcycles to fix a flat tyre, they gave my key to someone ells. After not being able to get my key back they said they would put in a new lock set. After a few days I had to phone them as they never came back to me. Then I found out that they were only going to make a spare key. I said I would not accept this as someone had a key for my scooter. After a long day of phone calls back and forth they agreed again to put in a new lock set and informed me that it would take about a week because they had to order a new one. A week later I phoned them again to find out when my scooter would be ready. I was told I could collect it that afternoon. I fetched it at 16:30, when I got home and looked at the lock set it was clear that it was not a new one. They were already closed so I phoned them the next morning just to be yelled at and told that I had a second hand lock set in and that's all I'm getting from them. I asked him why I had to wait a week for a new part to be ordered if they were planing on putting an old one in anyway but he just said they were not liable. Our agreement was that they would put a new lock set in and not to make spare keys.