Hi,
Personally, I'd try and go with something a bit more subtle.
"Due to the consistent increase in overheads (fuel, insurance), we are forced to increase our prices from time to time....etc etc" I'd go with that sort of tone.
I do not even know what the last sentence means to be honest, but if you are saying you have people cancelling (probably because they are trying to save money), then I'd ditch that. It looks unprofessional and could give people the impression that you are losing out on custom for another reason ie: below par service.