Small Claims Advice- Previous Rental- Failure to Pay back $900 Security Deposit

Hello,

Sorry for the long post but i want to be thourough so that i can tell the full story and hopefully gain some advice from you all.

I recently moved across the country to Los Angeles, CA, and in doing so needed to find a new place to live. I was able to find a place in which i did not need to meet in person to secure a room. After talking with the tenants who live there we agreed upon a $900 security deposit to be paid up front, before my move date to secure the rental. Then i would pay rent of $900 a month when i actually moved in. I was sent a "Sublease" from the tenant of the apt and was told to bring a copy when i moved in so that we can sign it in person. The sublease was already filled with some other renter's information and monthly prices that i suppose the tenant used in the past and i was expected to alter the document myself, filling in my own information. Anyways, when i moved in the apartment was a dump (not shown in the pictures i had been sent) and was not a good environment to live in. I paid the remaining 900 for the rent for that month though. The tenant never asked for or actually had me sign the sublease agreement. I also never had contact with the actual landlord. I found a new place shortly thereafter and gave a few days notice that i would be moving out. The tenant said he would pay me back my $900 security deposit and i have texts/emails showing this. However, after 3 months and attempts to set up payment plans with the tenant, he has not paid anything. I want to take him to small claims court, but am worried that since nothing was signed saying he needs to pay me my $900 back, the case will not go in my favor. However, i do have text/email messages which show him telling me he would pay me back. I am hoping someone here can advise as i do not have/know a lawyer i can contact for advice like this and $900 is a lot of money for me.

So once again sorry for the long post but i am just hoping for some help. Thank you