Firstly, dig out a fair amount, fill it with a strong mix of concrete, builders suppliers do a bag of ready to use harder mix for spot repairs etc, 3:1 mix with 20 mm ballast will be strong as feck.
If you're worried about the block pavers, mortar them back down around the anchor.
Thing with block pavers is, if you do see some sink later on, get them up add more sand, pale them back down
