Worst place ever

We have a Kenwood cooler and water purifier which stopped cooling the water. We contacted PMC and asked them if it would be possible for them to fix the machine and let us have it before the 14th December as we are on our way to our holiday destination. They said we must bring the machine in and pay R150 so they could see what is wrong with the machine first. They then contacted us and said it was no problem and the cost would be R550. We asked them to please go ahead. On Tuesday 8 December they contacted us and said if we want the machine by the 14th we need to pay an extra R370. We went to speak to them as that is not the agreement we had when we left the machine. We were quoted a price and given a promise the machine would be fixed. They refused to refund us our R150 and gave us the machine back. They are very arrogant and said we can contact any lawyer if we want. We would never have paid the R150 if they didn't assure us they could get the machine done by the date we needed it.