How do I remove glitched areas and blocks?
How can you remove glitched spots or blocks created by hackers removing items that they should not be able to remove?
A glitched area is an area that you can no longer place a block or you can't remove the item or block from that area :(
Solution 1:
In the 1.7 update (released on March 15th 2018), it added the /repair feature that world owners and administrators could use on servers. Type /repair into the chat, and you’ll be able to tap on glitched blocks and it will fix them.
NOTE: I haven’t tried this as I don’t own a server myself but I have seen posts on the forums about this feature.