Customer services won't reply and I need to cancel an engineer for tomorrow

[#1]

Briefly, I've been unable to make outgoing calls for weeks. Long protracted correspondence and 1 ineffective repair so far. Plusnet want to send an engineer to me home, told them I couldn't do Tuesday or Thursday this week and, naturally, they arranged it for tomorrow, Tuesday. I've been trying since Thursday to cancel but they ignore all forms of communication. I need to FAX them now, can anyone assist with the number? many thanks
Andrew

[#2]

Sorry to hear you weren't able to get through.
Unfortunately it's gone past the point of return so I can't cancel it now but I can confirm you won't be charged.