Drilling and grinding while customers eat

So my friend and I went to spur by the Durban harbour for lunch and as we were seated two men walked in and started drilling and grinding on top of a table not too far from where we were sitting. I then told one of the waiters that the noise was too much and we were feeling unsafe with all of this going on while we wait for our food. The waiter informed that people that were doing the work and they responded by saying they have permission from the manager to work. They further suggested I move from my table if I have a problem with the noise. We all know how loud a drilling and grinding sound as especially since they were drilling on metal. Unfortunately the waiters who were helping the two men carry the sign they were working on watched and said nothing. I then decided to leave with my friend and will not be going back there as my friend informed me that she once went there and while she was eating there were people painting the place, her dress got messed by the paint when she was leaving and she had no choice but to go buy something else to wear as she lives far and she still had to go back to work. It seems this spur has no regard for customers and I'm greatly disappointed.