Nowadays, are property agents professional enough to show us their temper and directly ask us to sue them after they let someone enter our flats without our consent after the completion date of the property purchase?!

My agent did not inform me that she just left my to-be-collected-by-me key on her desk freely to let someone else take it and enter my purchased flat. Then she still had no intention to let me know her action until I found evidence of someone(more than one)
entering my flat,
moved my furniture,
smoked and
even took(better say 'stole') my possessions!

My agent kept me from knowing all these until I made her confront the situation to me.
Instead of a sincere apology, she even shouted at me saying '
1. O yes, I really don't know why I didn't inform you about that ~.
2. Missy, I'm very busy ga. I don't remember it's today or yesterday that they entered your flat la!!

3. If you don't like it this way, go ahead to sue me lor!!!

At last, she ended the conversation by urging for her commission like this:
Wei, the commission is due lo wor, when will you give it to me?!

WHAT A TERRIBLE EXPERIENCE!!!!!!!
The worst part is, my new purchased flat is burgled before moving in! ><
I absolutely receive no respect from my agent and I question her professionalism and ethics. She couldn't even take care of her
Property Agent Responsibility 101 - keep the owners' keys right. 
The agent asked me to sue her if I didn't like the way she acted. Can I really do that? Is it a criminal to enter someone's flat without the owner's consent? even the previous owner after the completion date of purchase?
Please comment..