Failure to resolve query

I have numerous contracts with Vodacom that are billed on two separate accounts. On both accounts my data has been captured incorrectly. On one account there is a version of my ****en surname and an old postal address and on the other a grossly incorrect version of my marital name and an address I have never occupied. Numerous attempts have been made to rectify this yet I continue to receive invoices with the incorrect information. This is very frustrating and inconvenient. Each time I send documents I receive notification that this has been corrected yet it never is and so have resorted to this.