Simon r

I took it for a diagnostic it came back as a glow plug cylinder I think and an electrical fault with the maf , I was told these needed replacing so I had the work done alone with a short service and I still have the same problem , have been back 3 or 4 times now to have the computer reprogrammed and it keeps dropping in and out of limp mode still, after replacing the problem parts the problem is still there it seems to be getting worse now and the engine management light is now on I’m beginning to lose my patience with the place that did the work, if they couldn’t do it then why did they say they could

My insignia 2015 2.0 diesel has needed a service and oil change for a while , over the last month or so it has been going limp telling me to service soon, but then it sorted itself out , today the engine management light came on as I was trying to drive longer distance than Normal limp mode kept coming and going , any ideas please??