Unreasonable Billing and attitude

Took my bike in for a service, arrived at the place at 8h00 and they only started working on the bike around 8:20 and there was a tea break in between. the bike was ready at 11:30 and the workshop wanted to charge me 4 hours of labour, Of which I disputed and spoke to the manager. His response was that the company was there to make money. it ended up coming to 2.9 hours which I feel is till too much the job could have been done in half the time if the guys concentrated on their work.