In credit but being cut off.

Continually being cut off despite being in credit. Have spoken to call centre (including senior supervisors) about this with no resolution, keep getting told it is resolved. Happens each year without resolution, tried to call head of customer relations - no response. Why is there a need to revert to a public forum to get resolution instead of resolving a simple problem with the client? Multichoice’s billing systems are clearly flawed and should be investigated and rectified so as to be appropriate for a company of this nature.