Duplicate billing?

I have had a query that I have been attempting to sort out for a number of years without success. I have three email addresses but appear to be billed twice as I receive one charge for three emails on my normal Telkom account and then a separate email account from ********** for a further two emails. No matter who I call (faults, billing, sales), or try the online chat or email the idirect line back I get nowhere. I am not sure how to move forward on this.