Locksmith

My wife lost her House keys at 23:00. A locksmith came from Emergency Locksmith Gauteng to come and help. He explained the whole amount and after he opened the door and changed the butler door locking system his prices changed. After making a quotation from several companies the highest amount was supposed to be R1500 be she was charged R4000. On the receipt it states that labor is R3000. I am not sure why an advantage was taken or maybe it's because the locksmith saw that it is a woman. Please help.