ACCOUNT DEBITED DOUBLE

I have a query for months now where MTN double debited my account and they saying the can only see one debit on their system. I have sent them my Bank Statement were I have highlighted my account been debited twice, but to this date no one is coming back to me, and I have been calling their customer care line and every time I call I'm Being told that my query was logged incorrectly the last time. When I ask for their Accounts department contacts no one has their contacts or no one can transfer me to them. this have been going on since April now