Help - Paint Not Bonded

[stevo23777]

Hi I hope you can help me on here. I had my sons room skimmed - I waited until the plaster was pink as advised by plasterer. Mixed mist coat Dulux matt 50/50 (as advised by plasterer). When it was dry to be double safe I mixed another mist coat of 25% with the Dulux. Now I have painted with 2 coats of Johnstones Cova Matt, gone to put a stripe on the wall and the paint has peeled off even with yellow low tack frog tape. Does this mean my mist coat has failed and the paint hasn’t bonded? If so what are my options here to fix? Any help would be really appreciated.