Got car serviced 3 weeks ago

Got car serviced 3 weeks ago. Then last tuesday it wouldnt start, called out AA &they couldnt start it so towed it back to garage that serviced it. They said not their problem as it was ok for the last week. Took it to another macanic he ran a diaonastics and showed no faults. He chainged fuel filter still no start. He took off air filter gave a squirt of high octain fuel and it started no problem. He now says the fuel pump is the problem and it will caust €2000. To replace. Could this be problem or is it something simpler and he is trying to make a guick 2grand seen as one of his friends works in a brakers yard I found out