STANLIB withholds investments

I manage an investment account and issued withdrawal instructions which were acknowledged but not carried out. STANLIB decided to FICA and while undergoing the process froze the account. Despite complying they ignore emails. After listening to piped music on their help line for 30 minutes I had to hang up as it was clear that there is no will to serve their clients. What action must be taken. They are putting their clients in a bad situation not having access to their own money to pay taxes and wages. The Xmas break is looming and I suppose the office will close.