Frustrated by Momentum not paying

My mom has been struggling to get her retirement annuity for 3 month now. My mom went to the branch in thohoyandou to get her policy paid out on the 26 October. She waited for her payment and until mid November I help her call the call center to find out why the delay and was told there is document that was not complete( after submitting at the branch). I later on took her to centurion on west street to fill and submit the forms in November towards the end and we submitted everything. And since today she hasn't receive her payment. When I help her call to find out I always get the answer that it's in process and there is no outstanding document. It's been 3 month and she is still waiting. Please advice her in what else she need to do.