AIBU to think estate agents shouldn't of done this

[Shootfirstaskquestionslater]

Not sure if IABU or not I gave months notice on my flat last month on the day I paid my rent I gave the keys back yesterday I posted them through the door and they have put me overdrawn by taking another months rent today. I paid 1 months rent in advance before I even moved in. I spoke to my sister about it and she thinks that they shouldn't of taken the rent money today. This now leaves me in the shit and means any money I get in next week will be taken straight back out by the bank.

Thank you everyone I have now cancelled it and I will be speaking to the EA to get the money back. I never realised I had to do that but I know for next time. I realise it's my mistake for not cancelling it but I've never paid rent by standing order before so I didn't know I had to do that. Stupid me thought they just stopped taking any money.