Old Mutual Rewards hackers.

I am a member of the Old Mutual Rewards. I have points that I have been saving to accumulate and redeem them later when they have reached a certain amount. But my plans have been changed. There has been a daily routine of someone logging in into my account, using my exact credentials redeeming my points for Telkom airtime. It happens around 15:29 on weekdays and 13:30 on weekends. It's a daily thing. Whenever these hackers login, I receive an SMS from Old Mutual Rewards informing me that I have successfully logged in and redeemed points of a certain amount for a Telkom airtime. I did inform OMR and did not receive a satisfactory response and when lodging a second complain I was advised to fill in a sworn statement and change the password but since this hacker has redeemed almost all my points, I am thinking of unsubscribing because my data is not safe. I just wanted to inform anyone who may be a member of the OMR or any other portal that has rewards to be aware of this and I also want to advice them to change their passwords constantly.