Bajaj Finserv — unnecessarily calling and harassing but customer service

Website:

www.rblbank.com

On 3rd august my rbl bajaj finserv card was blocked as requested by me and all the dues were paid at that time.
Still i am getting call from bajaj finserv stating that i have to pay charges for blocking card and that is ₹4, 000.
Unnecessarily they are calling my dad who is a heart patient and harassing that they will charge penalty if this is not paid.
We are ready to pay the charges but since the card is blocked i don’t understand why this need to be paid as all dues were already cleared.
The customer service representative is not answering my queries and unnecessarily calling my dad regarding this payment.