cancel engineer without charge

[#1]

My fibre broadband has been off all day. I phoned Plusnet and they did a line test and said the signal was getting to the router so it must be faulty. An engineer is booked for between 8am and 1pm. The fualt has now cured itself at Midnight, so how do I cancel the engineer without charge, as no fault will be present. No 24 hr support?

[#2]

That is an odd reply, if they say the modem is the problem Plusnet supply the modem so would have thought they'd send out a new modem/router.

This warning of charge I think may be a standard statement whenever the word 'engineer' is used.

Geffers