Hi

I have noticed your post has been somewhat orphaned! Nevermind; here's what i think:
(1) deposit issue- standard approach,which you can learn from other posts about deposits. L/lord cannot withhold without a good reason, without evidence that he suferred some losses. No inventory, no such evidence.
(2)Your possessions and the post- l/lord is obliged to safely store your possessions for a reasonable time and he certainly
must return them to you (even if he says you owe him anything). Otherwise, it's theft, IMHO.
What I'd suggest: write to him (adapt a template from the sticky on top of the forum) requsting the return of the deposit
and your belongings and your post within 7 days. Say that you will be forced to (1) comence legal action for return of the deposit, (2) report a theft to the police with regards to your possessions and the mail.
By the way; whoever still sends money by post

How can you be sure that it arrived at all?