Paytm Mobile Solutions — unable to block paytm account with lost mobile number

Address:

170 NS Road, Sheoraphuli, Hooghly, Hooghly, West Bengal, 712223

I lost my mobile number [protected]. It was link with kyced paytm account bipratip niyogi.
When i tried to block the account by dialing helpline [protected] and following required steps, it asked me to enter the mobile number of the lost account. But when i entered the number, it said me the number [protected] is not registered with any paytm account, yet if i try logging in using the lost number, it is still sending otp to the lost number instead of popping 'number not registered' message. What king of service is this?