Salaries not paid as per contract agreement

I work for the above mentioned company and I have a contract with them but I haven't been paid for the past 3 months because of a certificate that was not paid in July and the blame was on me and my colleague that we ended up not getting our salaries and when it was paid I still did not get my salary and no one cared to explain why. In the contract I signed there is nothing that states that I will not be paid if the municipality doesn't pay the certificate and the original contract has my salary as R15 000 but I received a call that they will cut my salary down by R2 500 because they hired someone else which was not discussed with me before hand. The treatment of this company is beyond terrible as my colleague did not get his salary and also did not get money for groceries the same month. How do we survive? They don't care all they do is take holidays and flaunt about them while we can't even take our kids to school.