Using security deposit 4 last month's rent--shady landlord? (Mexico: real estate, apartment)

[positive_4life]

THIS IS KIND OF LONG SO YOU ONLY NEED TO READ THE 2 PARAGRAPHS BELOW TO GET THE IDEA! THX
I am seriously considering paying for my last month's rent using my security deposit because I am worried that the deposit will not be returned. In actuality the person I am renting from is not the landlord but the owner of this apartment. He is renting out his apartment since he will be away in Mexico for the first four months of this year. He wrote up a simple paper contract on MS Word which was signed by the both of us. Frankly I am not worried that this piece of paper has any legal weight other than to show whomever it might concern that I am entitled to be here till the end of February. Back in December I gave him $2000, $1000 for the month of February and the other $1000 for the security deposit. I will pay for electricity/water directly to the company.

The shady/unpredictable things this character has done which have broken my trust are as follows:

PLEASE< ONLY FURTHER READ THIS PARAGRAPH BELOW FOR A GENERAL IDEA, I KNOW THIS IS LONG!
-when I payed in December I payed for a 2-person apartment. He was still searching for the other rooommate at the time. However, about less than a week before I moved in (I moved in January 7th and he told me this January 2nd) he told me that I would be living with a couple. I was extremely upset that he would change the terms of the apartment. I payed for a 2-person apartment, not 3. When I wrote to him that he should reduce the rent for me he (I mean I have to share an induction burner with only 2 places for pots and no oven) said some bs thing like, "it's better for you since you will utilities will be cheaper". No, more like it's better for him since he is charging the couple $2000 per month! So he can definitely afford to reduce my rent, not to mention it is the right thing to do. My roommates are from another country so they didn't know at the time that they were getting totally ripped off.

YOU DONT HAVE TO READ THE REST TO GET THE IDEA..... THANKS FOR ANY INPUT!!!!

-he gave my number away to someone interested in renting my room when I leave WITHOUT my permission. I was surprised to randomly receive a call from someone asking when they could see the place. I told him not to give my number out without my permission and if he wants to show the apartment he will have to find someone to do it (I am not a real estate agent!). He apologized about it and said "it will not happen again"
-a couple weeks later he did the EXACT SAME THING to my roommates!

-his character evident not just by how he treats me but how he treats my roommates. Their friend who lives here found them this apartment ahead of time so my roommates did not see the apartment before they moved in. However, when they arrived they called the guy up (the renter) and asked if they could stop by to view the apartment as the guy was still here at the time. He said no, that someone was living in that room at the time. Turns out that the REAL reason he didn't want them seeing their future room was because it was filthy!! I arrived a few days later after them but apparently they said it the bad was covered in trash and old food, the bed was broken so they had to stuff the mattress with a ton of pillows, the floor was disguisting, the kitchen and bathroom too... they spend 2 days cleaning this apartment! And when they complained to him about it he said they could take my room! Like WTF?!?!?! thankfully they didn't because they had invested so much time cleaning their room up...

-his friend (who stopped by because we didn't know how to change the gas) referred to him as "a child" this guy is 40 years old! He is an artist and acts like on of these egomaniacal child "adults" who think the world revolves around them

-even my roommates don't trust him! Before I mentioned anything about my worries about the secruity deposit they told me themselves that they are worried about receiving their security desposit back too! And they are the type to remind me to split the for example gas bill into thirds, not half, as I forgot last time!

Basically, this is not a man of his word. I'm going to sound pompous but I take great importance in being an honest person myself. I do not do something like this lightly. I am only renting for 2 months and this place is in need of probably a hundred repairs (it is a VERY old apartment, it is poorly sealed, the wooden floor is literally disintegrating... I mean it's infinite) I highly doubt that I could have caused any damage... I am using his ****ty furniture (chairs that are falling apart, improptu desks, a frameless lumpy bed) so it's not like a moved in, I simply dragged my suitcase up the 4-floor walk-up lol. But I am truly scared of not receiving my security deposit back. This is the first time I am living in a big city, and I have never had something like this happen to me before, nor interacted with someone of the like of him....

Please help!