Bad experience at shell garage Polokwane Mall of the North Farm yard

Bad experience at Shell Polokwane Mall of the North Farm yard.Filled my tank from half, the next time the car loses power the engine shuts off while driving,I serviced the car only to find out its ther bad fuel.I called the manager and send her a text without any reply, a colleague of mine went through the same thing at the same garage and opened a case against shell but they never came back to him