How can I retrieve the money withdrawn through error. This has been confirmed as error through customer agents

08101900649
My personal account of #2,157 which I normally keep to settle my monthly post paid bill was erroneously withdrawn... Several customer agents have confirmed this. How many hours will it takes to recover the money. Post paid will soon request for monthly bill..... Again, some MTN customer agents are very rude and unpolite. It's like the particular agent (male) transfer anger on an innocent customer who struggle to put money into his account with harsh and Unpalatable words