Contacts for OPG Services Call Centre: Tel No: 0870 197 1404 - for general queries i.e. account balance, to check credits in/payments out, to stop Payable Orders, Payable Order status enquiries etc. Masterline Helpdesk: Tel No: 0870 197 1448 CHAPS/Internal Transfers (RFTs): Fax No: 01293 604044/604055 Payable Order Schedules/Stops: Fax No: 01293 551772/551781/604059/604017 E-mail address: opgservices@paymaster.co.uk