Credit card bill payment method would have changed so much over 40 years. Before online methods, we used to drop cheque in bank atm. What was payment method like in 1980s and 90s? Did you go to multiple banks to pay credit card bills?
Usually, all banks used to print n post the bills - with some promo leaflets in window-envelops. Such bills, have a counterfoil in the computerised bill. Almost immediately upon reciept, I/we used to issue a locally payable crossed cheque favouriing that Bank a/c CC account number. A few banks - like AmEx n Citi n HSBC used to enclose a blank envelope - either stamped or pre-paid envelope (postage paid by the receiver).
I/We used to drop either cheques or those envelops in any nearby branch of that bank. Or, send by ordinary post only. No courier. No registered post. No Online transfers, No Standing Instructionsv No Automated BillPays, No electronic transfers like NEFT/ETF, No eMails, No SMSs, No UPI, No Mobile banking or No Internet Banking. Only physical clearing of cheques. Reflected in physical ledgers n physical passbooks - manually written n signed.
No EMIs, No Fee Waivers, No Cashbacks, No LTF, No regular limit enhancements, No lounge access, No mis-selling by agents, No need to go to RBIO, No OTPs, No RuPay and No GST. No MCCs, No exclusions. No CIBIL, No Experian, No Crif.....
CC Life was much simpler. Not complicated like now.