Most bigger stores will have a counter were you pay bills. Often a money exchange there. load cards sold & such. Many banks near the ATMs have a bill pay on line. It is the machine the door opens up & you put cash in to pay. Like a Atm with select a bill pay on the screen above. But takes cash. Go to a Bank & buy a prepaid debit card. You put money on it then use the atm machine at the bank to pay bills. All you need do is ask around. Some one will tell you were to pay close to were you live. It is the Asian way of doing things. Thailand some 7/11s will have most all malls will have, most banks will have on line pay.

Most bigger stores will have a counter were you pay bills and, often, a money exchange, where you can load cards it sells. Many banks adjacent to their ATMs have a bill pay online; it is the machine door that opens up & you put cash into to pay. It's like an ATM, select bill pay on the screen above and it takes cash. You can also go to a bank and buy a prepaid debit card. You put money on it, then use the ATM machine at the bank to pay bills. 

All you need do is ask around; someone will tell you where to pay close to where you live. It is the Asian way of doing things. In Thailand, you'll find these machines where you can pay online in some 7-Elevens, almost all malls, and most banks.