Builders leaving damage and mess

dneezdneez

My builders have taken nearly 8 months to finish a 3 month job building a cabin. It is still not finished but just needs a few things done and a good clean up. They have destroyed most of the grouting in the patios and the paving is filthy. Should they jet clean and regrout? They said that there was some grouting missing and it has rained heavily, hence paving dirty so should not have to do it. I have some before photos which show the clean paving qand hardly touched grouting.
They have also destroyed some garden furniture, tore up a garden cover, tore one of my curtains, destroyed 3 brooms, a spade and shovel have disappeared, my 2 ladders are filthy and covered in cement. I have pointed all this out yet they have not offered anything .
They seem to be taking forever and haven’t been in all week. I owe them £6000 to be paid at end of build. I was promised all damage to be rectified and it would all be cleaned yet they are now not upholding their end of the contract and demanding money. Can I deduct the costs of the damage and insist they clean up properly and withhold their money until they do?