Has anyone else had problems with plaster coming away and cracks appearing on every joint of their MgO internally lined SIPs?

These cracks continue through coving and therefore cracking tiles.

We are informed that the walls were bonded with the wrong agent, but no one seems to know how to rectify this problem.

Suggestions so far range from filling them with acrylic, to completely re-boarding – the house is now complete, so this would be a nightmare.

We have tried easi fill, but hairline cracks reappeared within a month, although bowing to walls is better.

HELP!!!!