I upgraded my plan in the beginning of December

I upgraded my plan in the beginning of December. On the 25th of December my debt went of fine. On the 25th of January however they took a double payment. I am supposed to get a refund of R819 but it is impossible to get hold of a actual person and not AI assistant in the accounts. I just keep getting told that my frustration is understandable and they will escalate my query. But it's been 4 days now and no one has sorted my query out. I need my R819 refunded and I need to confirm that my debit order for 25 February was fixed and won't be doubled again. Can a human please call me and assist me?