Disgusted and unfairly treated

Me and my wife went to go eat out at the Dros , so she ordered an oxtail with mash, and i just a burger with chips. when the waiter brought us the food the oxtail (comes in black 3 leg Potjie) so when she brought my wife her dish the potjie was empty so we called her and she took it back she did apologise for it. We started to eat my wife had a bite of the mash and some of the oxtial (smaller piece of the tail) she poured the gravy over her mash and a big chunk of oxtail, she took a few bites and then she saw a hair in her food dont know was it in the mash or gravy. It was about 5cm long. We called the waiter again she took the plate and apologise again, then the manager came to apologise and asked if he could bring us 2 Don pedro's so my wife said she is still hungry as she just took like a few bites. Then the manager said "yes i know you are hungry mam so what you want to eat"? and she said the shell have the same (oxtail). The excuse was "then they have to make another portion" whatever that meant coz any dish they would have to make a portion of anyway, so my wife said ok let me then just take the chicken schnitzel. So we ate drank another beer and had one desert that we shared. When asked for the bill, they still charged me for the oxtail of which my wife had a few bites of . One would think atleast to keep your customers happy to atleast pay for what they actually ate, but NO service in todays life is just not there, they are just worried about their pockets! (Just Wondered do they even where they hair nets in the kitchens)