1997 Ford Mondeo has to be hydraulic lifters

hi my st has been making tappet noises, i got mobile mech to come to fix it, now the noise is worse and my mech wont come back, says alot huh.so far i have bought 17 lifters, i have taken front rocker cover off, but im not to confident of releasing the lifters as mech donr it without removing cam, i have 4 cams,
any1 near ramsgate know how to do this and can help, i have had to buy a new car to run about in while this is being fixed, am out of cash and patience, please help me. ps mech been on phone saying he now wants to take the heads off, i need some1 i can trust not o screw with me and give me some advice.pls
paul