PayByCash provides a wealth of payment options to grab your membership or spins. How long your payment takes to process depends on the method you’re using.
The majority of PayByCash methods, such as Ultimate Game Card or paysafecard for example, will be processed the moment you complete the transaction, leaving you free to plunge right into the adventure.
Certain other methods, such as Bank Transfer, E-cheque or Directpay 24, do have longer processing times, although these vary between each option. For example, a bank transfer can take from 2 to 5 working days.
For more in depth info on how long each PayByCash method may take, head on over to the Making a RuneScape Membership Payment page, select your region from the menu at the bottom of the page, and hit ‘PayByCash’ from the menu presented after selecting a region.
This is an answer from the Billing FAQ page found here