Poor woeful service utterly disgusted

Very poor service from Momentum. I have been trying to submit my tax return but I cannot seem to do that due to a message popping up every time. After numerous calls to SARS where I had to hold on for hours they send me back to Momentum and SARS is adamant that it is something that Momentum needs to fix because they cannot do it from their side. I have sent numerous emails to which they don't respond. The message I get is as follow: PLease note that SARS will not process the return, there is a finalized tax directive processed, but no lump sum amount is declared on the return. Please contact the fund administrator / employer to rectify the error and submit the rectified return. And don’t tell me you will send me the irp5 that shows the amount that was taxed from my pension payout I have that thank you. How do I fix this and submit my tax return