Use stainless steel wedge anchors:
https://www.hilti.com.au/c/CLS_FASTE...E_ANCHORS_7135
Once you remove the tile, drill the bolt holes to suit suitably large wedge anchors with the pier base in place to make sure the bit doesn't wander about.
Install the wedge anchors and use thin fender washers to get the pier level.
Then remove the pier and mix up some non-shrink grout (leaving the levelling washers in place), pour the grout into the recess and re-fit the pier tightening down fully. Then clean up the excess grout that squeezes out as you tighten the pier.
All done, go and enjoy a cold beer.....