Ford Fiesta please help injector seals fixed by garage but now no power

Hello I'm new hear... I've had a good read about and read up on injector seals... I didn't want to try and fix them myself but now I wish I did... so I dropped my car to my local garage to have the injector seals done...before it went in it drove perfect nice and nippie only a ticking noise and the smell of fual ..so they had it for the day from 8.30 and called at 6pm to say it was all done but as soon as I took it for a drive I could tell something was wrong it had no power like the turbo wasn't working ...so I took it back to the garage first thing in the morning and told them that it's feels flat and there's no power so they said oh it's ok maybe the vacuum pipe was left off ...so I left it with them went back they told me again yer it's all done it runs lovely ...but no when I dove it still no power ..so I took it strate back again they said leave it and they will have a look at it again they then said they can't find what's wrong it maybe the air flow meater so they changed that still no luck ...then they said it could be the ECG so they plated that off to try that ...but guss what still no joy so they tried diagnostics mec  to find a problem but come back with no faults ...then they got another mechanic who only deals with deasel cars he looked at what they had done and said he can't see any problems with there work ..so he got he's diagnostic mec and he didn't come up with any faults..and then he said he would come back monday with a better diagnostics that can look deeper... and then they said it could be the ecu and that could be expensive to fix ..so they had the car for 4 days I got it back for this weekend as I had to go somewhere so I took it on the motorway wow it was painful not to say dangerous it just about got to 70 mph I could not overtake as there's no power I have to take it back in the morning ...monday ...for them to take a look again so I was wondering if anyone on hear has some advice for me... Could it be that they have damaged the injectors thats why it driving like this please can anyone help thank you very much..... crazydan