Old Mutual refuses to escalate Pension Payout

I have at least three pension policies with Old Mutual, the last three were taken out about 4 years ago. As I did not require a large monthly payment, I opted for a low starting amount, as I was told that I could increase the amount annually before the anniversary date, and that I would be informed when that was due. I have not requested any increases, but I now need to increase the payment. After hours of waiting on the telephone, being transferred from one section of Old Mutual to another, being told that I was still at the wrong section, I eventually got to a person that could look at my policies. I was told that I could not increase the payments, because they were payments for life, or something like that. My present payout hardly uses the interest on my investment with Old Mutual. I cannot live off the payment now, how will I survive in 10 years time. I sent emails to 6 Old Mutual departments on the Internet a week ago asking for help from the correct department. Not ONE of them bothered to contact me. Only the complaints department phoned today, a week later, to find out if my problem was resolved. She then offered to put me through to the Call Centre. Not AGAIN!! Please HELP!