Not a lot you can to unless you track him down. We had this problem with a tennant. He pissed about a lot. Missed one payment then paid the next. Then we sent him a letter saying you have 7 days to pay up then he'd do that.
Then he stopped paying all together. DH knocked at the property to no avail. For weeks we tried to contact him. The house looked dark. Then DH & I went up together to tackle him. Used our key to get in & it wouldn't work. We thought he'd changed the locks.....which he hadn't.
Turns out he was in the property all the time.
I got pissed off on Boxing Day 2006 & went up with a letter telling him to leave by 8am New Year's Day 2007 or we'd break in the house to find him.
Went up at 9am & he'd left!!!!!!!!!!! Hooray!!! Got our house back. Left a telescope, keys & log book to a campervan he had in the garden (we sold for £1600) & endless amount of disposable gloves & those little sealy bags. i suspect he was dealing drugs from that.
He was an electrician & the bastard bypassed the meter so had free leccy for month. Shut the blinds & curtains & even put a brown carpet on the door - nailed in to stop the light.
BUT...what pissed me off more than ever is we went though an estate agent (very well known where I live - one of the biggest) & they said he had a CCJ in his name but it was now cleared. We paid them to do proper checks.
Glad he was out of the place cos its now my dream home. For a few months we got letters from companies after his money. Took a long time to tell them "he ain't here"!