Sounds as if it is forwarded.
Hit the line on any phone, then dial the clear all features code, or the cancel call forwarding all code.
If this doesn't work, find any other phone, be sure it's class of service alls it to "clear all features remote" and then dial the Remote clear all feature code + the number of the line.
That should clear it.
BTW - I have an open ticket with your partner. No problem if you need me to work with you. Just call.
Ralph