Gordy7:
Step daughter chopped through her fibre cable just inside the boundary. Similar to OP situation.
2degrees/Chorus repaired the cable pretty quickly. Edit - never got charged.
Don't know how the join was fixed.
We had a second line installed years ago for Internet connectivity. It wasn't buried properly and ran through the garden. When it eventually got chopped, we didn't pay a cent to repair it, nor should anyone who accidentally breaks the fibre when the installation is so shoddy.