David,   I made an additional payment of $10 and calling to 13 number now works. Looking back at recent TPG invoices does not show the original charge for pre-payment, so that is the answer. Thankyou   Shane,   Thanks for checking in, my suggestion of a line check is not required as the issue was financial.  It would be good if we received some notification of attempting to call out without sufficient funds, either on the same call in place of an abrupt engaged signal or later via email.   Thanks to you both for helping. ... View more