i have recently letted my house out to a polish family..?

well they are not a family but friends that know each other.
I exchanged contracts on 19th may, and their demands were that i paint the kitchen for them, and change bedroom door, and give another double bed, and sort toilet area out which i have completed.
they gave me 700 deposit and said would give me remaining 200 after completion of work. I have finished painting the kitchen today and asked for money but they keep being rude too me, It was part of terms and conditions on contract. Another 900 payable every 19th of the month. When i rented out house back garden was clean but now they have taken a dressing table and put it in the garden and carpet that was in the kitchen outside in the rain and said they want it cleared. Surely i shouldnt have to clean their mess, where do i stand legally as they are very rude. Contract is for 6 months.
i purchased a ready made contract from w h smith. terms and conditions were in small print. Stating clearly if any damage was occured money would be deducted. I cant throw them out as its a six month contract.