Pruning of these should be done in midwinter when the plant is dormant, and then usually only to remove dead wood, though a light trim back after flowering can also be carried out. Malus usually flowers in late spring - as we're four weeks behind this year, we're not yet there, so hopefully, your tree will eventually come into leaf, if not flower (there may be none this year if you pruned it hard).

Thank you. I will keep my fingers crossed that it will come into leaf.