HDFC Bank — activating one assist service after cancellation

Address:

New Delhi, Delhi, 110017

Cancellation of one assist membership
I am a hdfc bank credit card holder. The bank has auto debited rs. 1399/- from my credit card number ending 2093 even after cancelling the service and sending them request by sms on "stop oa" on no. [protected] on 21 dec 9.02pm.
And i have received 2 messages from bank 1st is
Dear customer,
We apologize for the erroneous debit of rs 1399 towards oneassist plan. Reversal will be processed in 7 working on your hdfcbank creditcard. On 27 dec at 03:11pm

2nd is
Dear cardmember, oneassist membership fee has been debited on your card ending 2093. Membership will be processed and welcome kit dispatched shortly. On 27 dec at 03:56pm

I search on their app and web and thier toll free no. [protected] is not even a valid no. And on other no. [protected] there is no such option at the end.

I am not interested about this service and don't want this membership any more. So cancel the membership and refund this debited amount of rs.1399/-

Name :- narender singh
Credit card number ending :- 2093