Mobikwik — Unauthorized credit card transaction

Hi, My husband is using CITI credit card with maximum limit 75k per month. He had spent 35k and had the remaining amount around 40k. 20k was debited first and again around 20k has been debited with credit card yesterday(30/09/2020). He came to know this after receiving the SMS. Third time credit card has been blocked by the bank.

He reported the same to CITI bank. The customer care said that it was transferred to foreign account by using Mobikwik. This incident wouldn't have happened
1) if Mobikwik do not allow such a huge amount transferred in a single transaction.
2)if Mobikwik had taken care of the customer details.
I would request Mobikwik company to take responsibility for the incident and refund the amount.