Octavia II RS boost problem

Hello,

I have a 2007 Škoda Octavia RS, with 2.0T engine and manual gearbox. There's no boost on low revs at all, it pulls a bit starting from around 4k but it feels it lacks a lot of power. Visited a repair shop, they made pressure tests and checked for leaks- all good. Then they thought, it might be the issue with the wastegate. Supposed to be common problem with these engines that the wastegate wont close properly  not allowing the boost to build. They adjusted it and yay, car pulled like a train after that, still spinning the tires on tarmac in 2nd gear. For a few weeks :|  Now the problem's back and it even seems worse, then it was originally or just feels like it because the car was running awsome just before that. Havent found much from the internet on that subject, maybe I just dont know what to look for as english isnt my 1st language

Help/suggestions would be much appreciated.

Thanks,

Martin