Sounds like you're disabling the voicemail service, not conditional call forwarding. Try dialling ##004# - it's the GSM standard code to disable all conditiona

Sounds like you're disabling the voicemail service, not conditional call forwarding. Try dialling ##004# - it's the GSM standard code to disable all conditional call forwarding rules. More codes at https://support.t-mobile.com/docs/DOC-4041 https://support.t-mobile.com/docs/DOC-4041