Unauthorized Transfers

@FNB transferred R2500 from my Cheque account without my approval or conesent into a different account(which in arrears- whereby a different arrangement was made)I received no communication and did not authorize the transfer and was subsequently told they are within their rights to do so according to their reserve policy.I am unable to reverse the transaction and was transferred to 5 different departments without any reasons other then the person who did it does not answer their calls . I simply just received an in contact message saying the transfer was made . Worst service I ever received after being with this bank for over 10 years . For my ‘trusted bank’ to literally take food out of my mouth and use the excuse of ‘ we don’t know why this happened ‘ ‘ just accept it ‘ is not only unacceptable but really disheartening. Me and my family ( and there are 5 different account holders ) will be moving immediately to a different bank .