Shocking treatment at Nissan; South; Durban.

I have been to Nissan South Durban (cnr of South coast rd and Solomon Mahlagu dr) 5 times for a faulty fuel gauge. Yesterday I picked up my Renault Kajar from them with no guarantees the problem is solved. They seem to think that because it's being done under warranty, that I should be grateful or something; not considering that thus far it has cost me around 10 hours pay and messed up my attendance register at work. One particular individual, Musa, has been totally unhelpful and inconsiderate to the extreme. I am now simply lost as what next to do if I have to go back a 6th time for this problem. If anyone has some suggestions as to how I can escalate this shocking treatment, I will appreciate it.