AIBU to argue with plumber's invoice?

[Cloudysky]

Plumbers gave us a quote for some work which they estimated would take 6 hours, but the guy spent less than 3 hours on site (& quite a lot of the time on the phone) so is it reasonable to say I don?t want to pay for more than 3 hours labour?
I'm happy to pay for a good job and don?t want to quibble but at 70 quid an hour it?s not nothing...
The guy also said we needed further work and ?might as well? get a new boiler (they call themselves ?ecoplumbers? which I?m finding a bit ironic as he said only one part needs replacing!).
Help! On maternity leave and obsessing way too much that I'm being ripped off. How do sensible, sane ppl deal with stuff like this...?

[sayithowitis]

I think it depends on whether you obtained a quote or an estimate for the job. What does it say at the top of the letter? difference between quote and estimate this might be worth a look for you.
if it was actually an estimate, i might be inclined to query the final bill, but if it was a quote, I suspect you are stuck with it.