Kotak Mahindra Bank — sip gets deducted even after stopping the same

Address:

Rangareddy, Andhra Pradesh, 500035

I stopped my sip on 25th march and redeemed the entire amount. But they are still deducting amount for april month also. When i asked them they are saying to redeem it so that i have to pay exit load again for those units.
And they say it is 30 day procedure for stopping an sip.
This seems very unprofessional. I want my money refunded into my account.
Please resolve my issue as soon as possible and make amount credited into my account.