Tamil Nadu Electricity Board [TNEB] — 3 failed upi transactions amount not refunded

I did a payment to TamilNadu Electricity Board on 11th March 2024 via BHIM upi app. I tried three times and all of them failed. I later realised that amount was deducted but, till date I did not get the declined money back to my source account SBI. Each transaction was for 8849₹. In total, I am awaiting amount of 26547₹ back to my source account since 11th March.
I have raised complaint to BHIM, SBI BANK and TNEB too. SBI says to reach to merchant to get the money back. TNEB does not even attend calls. This is causing immense stress. As its a high value amount, I really need your help to refund my money