Quoted for a job far more expensive actual repairs

We were quoted to fix a full portion of our fence. When the guys came to fix it, after calling a number of times to actually get them here, they had the wrong number of fence struts and the incorrect supports to actually complete the job quoted for. They made a plan however and just welded 3 spikes onto the top of the existing fence. We emailed them to explain what happen. They still told us we had to pay the full amount. They even changed their invoice to say the amount was a call out fee just to suit their greedy back pockets. I would have never paid R4000 to weld 3 spikes onto a fence. Shame on you. I hope your ***** business practices loose you a lot of clients.