Refund due on expenses incurred

I bought a used VW Polo from Xquisite Auto. The car was delivered to me and I found that the driver's window was malfunctioning. I took the car to VW for a service and VW had to undertake additional repairs. I contacted the sales person and he promised to refund me. The sales person subsequently resigned and directed me to another sales person. This sales person never ever responded to my messages. I got a hold of Naseem who appears to be the manager/owner. After numerous promises, I received a partial refund. He has not been respnding to my messages since then.