Outstanding IT88 payment to SARS

Outstanding IT88 payment to SARS. This is very frustrating that Investec is failing to pay SARS on my behalf and the outstanding amount continues to accrue interest.It was very easy for them to deduct this amount from my sales but it difficult to pay SARS. Refiloe Molebiemang always promise to do a follow up with their tax department and get back to me via email and when I call all their Consultants promise to get back to me. Can someone please resolve this issue for me