Jurist gezocht: please help to understand how to deal with this case

Good afternoon,

I am living in The Hague in an owned apartment.

In 2011 I bought in verhuurde staata complex of three apartments in Rotterdam. At the end of 2012, one of the apartments (rented at 875€/m excl.) becomes free so, only in summer 2013, I contact multiple makelaars to have an evaluation and to find new renters. The average price they propose me is 900€/m excl.
Since I was not interested in a high price, but more in a quick rent, I informed one of the makelaars that I was available to a lower huurprijs. They proposed me a lady for 750€/m excl. which I accepted with a contract starting in September 2013. I never met her, since she found an excuse at the day of the signature.
As a welcome gift I gave her a dishwasher and a clothdryer, originally not included in the contract. I called her afterwards and she sounded extremely happy of both the price and the house conditions and my gifts. However ... since then, she 'stole' the furniture in the apartment, that I was clear with both makelaar and her I needed back in The Hague, she stole a pin automaat (value 490€), that I had to give as a present. She didn't transfer the electricity, the gas and the water at her entrance. So in the end I paid for her Sept and October utilities. I was verbally threatened by a friend of her to stop requesting back the pin automaat, so I would have serious consequences. I decided to give up.

The neighbours started to complain about her. But I tried to leave things calm. Already from November she started to be in delays for the payments and finally she stopped in January. She claimed that I had to pray God or, even, go to a church to ask for charity if I needed money ... I started to believe that she was not good in her mind.

In March she informs me that she was obliged by the gemeente Rotterdam to let them in the apartment and that they decided that the price was 432,81euros/m maximum.

I called a lawyer asking for an all-in price. However he could not really handle such a case. In fact on 17 April the huurcommissie has made the investigations. As a prevention I have sent the pictures of the apartment taken by the makelaar before the rent where they state that the apartment was in excellent conditions. This lady, two weeks before the huurcommissie onderzoek, writes an offending letter to the gemeente to the huurcommissie and me in cc, where she says that I am a criminal, that I act illegally in the Netherlands and that she feels sick about my greed for money. She is disgusted and misselijk by me. ...
Unfortunately my lawyer does nothing. So I contact the politie wijkagent in the area of the apartment to inform. Now she complains about the neighbours because they listen to music at 7 am. I contacted them and it appears that they go to work at 4am every day... So... I feel really abandoned by my lawyer.

As a last thing, I receive a letter from the gemeente Rotterdam where I risk a fine of 2000€ since I didn't aske for a huisvergunning. I didn't even know what it was since then. I am surprised by this, since I went plenty of times to the gemeente to inform them that I had renters in the apartments and no one told me that I had to ask for a permission. In addition not even the makelaars have ever told me about this obligation and in the end, the previous owner and the notary sold me this apartment in 'verhuurde staat', where also the taxatie reports information about the value of the area and so on. No mention about this weird rule.

I would appreciate a discussion to understand how to deal with this case. If I could have a fixed price for some lawyer competent in the matter. I finally inform that I have a special status in the Netherlands, a sort of diplomatic immunity, that defines me a non-resident citizen in this country.

Thanks for your support. I would be glad to be contacted after 16.30 in the afternoon.