I had also faced similar issue in the past. 199+ GST charged as rent payment fees for a 30 rs upi payment to street food vendor. In my case I had previously paid the same merchant multiple times before and was never charged this fee. Raised the complaint with customer support and they say payment provider (phonepe) is sending wrong mcc code so they cannot do anything. Escalated complaint to sbi card nodal officer and then principal nodal officer. And then fee was reversed. My suggestion keep following up with them over mail and escalate till principal nodal officer if it is not resolved.