Poor Service - Unresolved Issues

For the past two years I have been unable to renew online, maturing Fixed Deposits. The telephonic support centre could not determine the problem and was unable to assist, but assured me on both previous occasions, that my complaint was logged and would be resolved before the next renewal date. As a result I had to physically visit a branch to renew the Deposits. Now for the third consecutive year I am unable to renew online, maturing deposits. Despite the lip service given by Nedbank, obviously this problem (maybe unique to my profile) has still not been resolved. I have tried every possible permutation of renewal options, yet this facility will not work. Each attempt results in the error message "Instrument Type Invalid. Result Code RFD_R62)" What do I have to do to get Nedbank to actually follow through on a service they purport to offer?