AA
Error - Insufficient credit
A3
Error - MSISDN not recognised by the mobile network
A5
Error - Operator Bar on this MSISDN
A6, A7, A8, A9, AB, AC, AD
Error - MSISDNs expenditure limit reached
D4
Error - No consent found to charge this MSISDN
01, 48, 74, A0, A1, A2, A4, AF
Error - Billing attempt has failed