Micro sol is a decal softener, micro set is used first to help it stick and, to a lesser extent, suck down onto the model. If ut still doesnt pull down THENa decal softener is used. Some decal solutions will literaly destroy some delicate decals. Use with caution an test with a decal you wont use first.
Last time i used xtradecals i used gunze mr setter and mr softer and it worked great.
If your decal is still in good condition i would suggest soaking it in the setter solution until it is movable again then,wick off the excess solution with a tissue, wet a SOFT cotton bud with waterand heat it overa flame to make it warm, and gently roll (DO NOT RUB!) the bud from the center out flatening the decal down. i advise practising on a scrap decal first. If after it is dry it still wont sit down, then try the softener. You can try the coton bud again but this will destroy some decals after a softener has been used. Most ppl including solution/decal makers say use a hairdryer instead bu i never have.
Your decal may just fall apart, i dont know, try this at your own risk and responsibility! And practise first.