Old Mutual is Holding MY Money to Ransom

Maybe it is my stroke acting up and I am loosing touch. But, I invested MY MONEY into Old Mutual with the idea of receiving a monthly income. All of which has worked fine so far. So the wheels have come off. SARS is after me for money, I have to undergo an operation for which my medical aid will only pay 50%, and I am no longer able to use a manual wheelchair. The orthopaedic surgeon has motivated to the medical aid that I have to switch to an electric wheelchair to prevent any further deterioration. I asked Old Mutual to release the necessary amount, and guess what? Old Mutual refuses. As if it is their money. What am I missing? Old Mutual is holding my money ransom. I know that there will be an impact on my income, and will be happy with it. The current income will be of no use if SARS sends me to prison for not paying taxes. Any thoughts?