Hennies Hartenbos poor service

We arrived at 19:00 at Hennies Hartenbos (We were a party of 13). We ordered drinks at about 19:08 the drinks came and first thing my beer came with black bits in the foam. The waitress was very helpful and immediatley replaced the beer. After that we were fine the waitress was a bit scarce but it was sort of busy so that's fine. At about 17:38 we ordered food and we expected it within a reasonable time, but after an hour and ten minutes we asked for the manager. The first person told us the manager was upstairs and that he would call him. Then he continued waiting on a different table and cashing them up so I went upstairs and the person behind the bar upstairs told me he was downstairs. So I went downstairs and asked the person behind the downstairs bar to please call the manager. So in conclusion the service was poor and when trying to adress this they gave me the runaround to talk to the manager. And on a seperate note when we wanted to order more drinks they said we couldn't order and pay for the drinks at the bar which seems bogus.