Excessive engine oil

Hi I sent my polo gti to barons pmb on the 1st of September 2017. 3 weeks after using my car i had done like 650kms, the engine oil light came meaning the oil was low. This is impossible to happen as my car was just out a service. Took it to barons then they had refilled engine oil. 4weeks after topping up I had done 1200kms when I discovered an usual sound on cold start. Checked my engine oil and it seemed to be over. Polo gtis take 1litre of oil per 2000kms. I had done 1200kms and the oil was still over full. The other day my car started misfiring and the EPC light came. Barons is saying that they've done a wet and dry test of which piston 3 and 4 had low compression. What i would like to know is if excessive engine oil can lead to this happening? Barons pmb is unable to cope with the amount of Vws in pmb. Hence we have such poor service due to there being no time for them to pay attention to our vehicles.