bad service

last month i took my car to the supa-quick in mitchels plain since its much closer to where i live, i advised the technicians to do a full inspection then tel me whats wrong with the suspension, they advised me that only the cv joints needed to be changed and i had my voucher for the wheel alignment which i bought on groupon. when i left the car was riding fine, the problem started last week when i noticed the car was somehow swerving even when driving straight, and started to be wobly, i dont even drive to work during the week, only utilise the vehicle during weekends. i am very dissappointed by the service received and i refuse to pay a cent extra, i need this to be resolved before something serious happens to the car.