Will I be fined 3 times deposit amount?

Tenancy Deposits

The property was in 'brand new' condition after a 45k refirb.

They moved in & the property became the main party house in the area.

When they finally moved out, they left unpaid utility bills, damaged furniture, left holes in walls, didn't return their keys, the list go's on.

There was also some unpaid rent.

Now they want their deposit returned & I didn't lodge it in a tenancy deposit scheme.
I'm worried that I may also get stung for 3 times the deposit along with the costs of returning the property back to a lettable condition.

Doe's anybody have any info on the subject?