Received rates statement on a property that's sold

It's really a shame that i contacted the municipality reagrding this matter is Sepetember after the bond was registered to a new owner on the 5th of August already and was advised that it's still earlly after the reqistration that's why ofwhich i did understand and now again i have received another statement stating i'm owing the municipality R121-10, FOR WHAT? Why in my name as the property is already owned by someone else? what really irritates me the most now is the fact that i even still receive smses for Newcastle municipality which just shows the level of cometency is too low.