Hello, as a bt customer am i liable to pay bt for repairs to the GPO junction box inside my house?

i had a bt engineer out and he replaced the wires inside the box as they are corroded, 10minutes work and they have sent me a bill for �130 however ive heard from a retired engineer that i'm not liable to pay this as bt should have replaced these boxes, i can't seem to get a hold of anyone who understands at bt