VXOC Astra-J/GTC

Hi chaps,
Im looking for a bit of help here please...

I own a 2014 GTC 1,4 sri which developed a fault last week. Was overtaking and suddenly there was a loss of power limp mode and got the 'service vehicle soon' light show up. So drove car straight to the garage to be checked out. Fault codes P0229 (boost pressure) and C055C (steering box power performance failed) the outcome was turbo had blown due to oil being too thick as i hadn't had it changed for a while so i thought yer fair enough. So new turbo, pipes, filter, oil and flush cost a few quid but while driving home from garage the exact same thing happened again?? Obviously im going to take it back to the garage but any help would be really appreciate please. cheers

It could really be anything without plugging on and seeing.

One thing that comes to mind is if they learned the new turbo.

Cheers Rusty not sure what that means though?

UPDATE - started car up today and service error has disappeared and car was driving fine until i put my foot down and now its happened again! service light and limp mode back..

Another update - Took car back to the garage today and the new turbo has also gone, what could be making this happen any ideas?