Promise made not met

I wrote a complaint to Vodacom regarding them incorrectly debiting billing me .when I received a call from them saying they apologise and will fix all amounts they have taken incorrectly and to be credited back to my account , today I went into my bank again only find out that Vodacom instead of refunding me they debited me again incorrectly ! I am totally disappointed shocked ! with the service , duplicating debits and it is costing me unnecessary pain and hardship ,Barry