In the door expecting R250 Out R4000 later

I took my car into TnT Newmarket Mall Alberton for a slow puncture probably due to a nail , I left 3 hrs later with a R4000 bill , all 4 tyres were removed for some reason , I did specify which one had the leak , I was then told that all 4 rims on a 2yr old car which has only done 30 000 km and only goes to the local shops and back we're bent and needed to b straightened , I was quoted R750 in the bay and not knowing anybetter thought I better have it fixed . Only after I left still in absolute shock from the bill did I realise that that was highly unlikely as I would have remembered hitting so many harsh potholes , and there was no amounts of R750 on my invoice???? Great to know who to trust , they won't see me or my husband's business again .