Pathetic service

Me and my family went out for dinner on Friday night which we served by a waiter called pk which took out orders and it took some good long time to come and when it comes it did not even look appetising while they were things sgortinh from the plates which needed to be requested but we just ate as it was long that we have been waiting where by our glasses of water were very dirty which we noticed half way when drinking the water when we were done with eating we paid our bill and we tipped her according to the service that we received but she insisted that we tip her 60% of our bill which was 680 as per this waiter it is compulsory that we tip her the 60% which made me furious cause we never received the 60% service and from when is it compulsory for a customer to pay tip by force from a waiter did we come to the restaurant to pay people salary or eat and pay for what we eat I don't mind paying a tip to someone who deserves it but not someone who orders me and I have read complain about this spur which is coming out of control and it seems that no one is taking note but we suffering with the bad service while we need to pay our hard earned money let someone get they acts right !!!