I have pistons that were moving blocks, but when the realm they were on got shut off for maintenance, it glitched it and now I can’t remove them or affect them in any way. 

How can I remove them?

Steps to duplicate;

1) create a constantly moving blocks with a piston feedtape and leave it running while you are in the same chunk 

2) wait for the realm to shut off for maintenance 

3) join back onto the realm