Airtel — Payment for Jan 2021 bill made but not accounted for

Jan 2021 bill for Airtel No [protected] received on 03 Jan 2021, was paid on the Airtel Portal using my Citiank debit card (No ending 2013) from my Citibank account No ending xxxxxx808 on 03 Jan 2021, and tis debited to my a/c on 05 Jan 2021. The Airtel portal for postpaid mobile does not have the feature of forwarding the transaction to a email id or to print the transaction page - this feature is present in landline/broadband. Hence the payment transaction reference No which is 210103xxxxxx was not noted by me since I did not have any issue till the payment of Dec 2020 bill. Since 30 Jan 2021, I have been a) hounded for the payment which I have already made on 03 Jan 2021 b) asked repeatedly for the Reference No which I did not note down c) being charged for Late Payment Fee of Rs 100+GST d) services have been suspended, pending the payment of "outstanding"/"overdue". I have made subsequent paymets of Feb 2021 bill on 14 Feb 2021 (Ref No[protected] and Mar 2021 bill on 09 Mar 2021 (Ref No[protected]. Somehow the 03 Jan 2021 payment has not been accounted and I have submitted the Citibank payment alert mail date 03 Jan 2021 when the amount of Rs 470.82 (being the bill amount) was debited to my a/c and credited to Airtel. The actual debit to my a/c in Citibank was made on 05 Jan 2021. I have even submitted my Jan 2021 Citibank statement in PDF form with the password to access the detailed statement, and to prove that the said payment was not reversed. I written to 121 & Appelate.kk where I have been put into a loop - every time the mail response is the same - its asks for that elusive Reference No which I have not noted down. It is more that 2 months and there is no resolution in sight to this deadlock. From my side, I confirm I have made all payments and within the relevant due dates and yet I am being treated as a defaulter/late-payer. Request someone senior and intelligent and diligent to please close this matter once and for all. Thank you.