I lost money due to the wrong IRP5 submitted

At work we used to use Momentum funds at work, we were then transferred to Discovery. To my surprise Momentum sent an IRP5 that says withdrawal to SARS. Sars has garnished me R4000 so far and looks like it’s going to be more… since I have been calling and told they will call me back. Since the December I have been calling told a case manager will call me till today… I am still waiting