Same thing happened to us
I just got back online, and I was going to add this story to my "trip report", but I guess that it will fit in here.
We rented a house in Perla Marina, Sosua for three months. We had a "contract" via email, and we deposited the first month's rent and a month deposit into the manager's account. We discussed signing a longer lease with the manager, but we did not commit to anything (edited to add: We actually made it very clear that we would not be staying, and the manager even sent her friend over to take us to Cabarete to look at the friend's house), nor did we get the long term renters reduction in our rent.
We gave a month's notice that we were moving to Villas Karibik, and we left the house clean and in good repair. (The place was badly in need of paint when we moved in, and my husband fixed all of the screens)
When we tried to get our deposit of $800 bucks back, we were told that we could not get it back as we had made a committment to rent long term. We told some friends about the issue, and they recommended an attorney. We hired a Dominican attorney, who told us that this happens all the time to Americans. Apparently we should have used our deposit as our last month's rent. Anyway, the attorney said that it would be $2000 pesos if we won, and only the cost of the legal stamps if we lost.
Since we had made the contract via e-mail, we had a contract valid under American Law and not Dominican Law. ALWAYS sign a paper contract in the DR. The manager backed off about the supposed "committment", but she told the attorney that she had to pay $40 US to have the house cleaned. Now, I know for a fact that she pays the maid 200 pesos per day to clean the rental houses. Plus, our maid had spent the day cleaning the house. The manager also stated that the house needed painting and that we must pay for the paint. Two of the four houses had just been painted, and the gardener was in the process of painting a third (which the manager was living in). So, for some reason, we were the cause of the faded and peeling paint in our rental. The attorney put some pressure on the manager, and , since she owns a VERY large hotel in Cabarete, she agreed to pay back the deposit minus the cleaning and painting fees.
Then, she had the nerve to say that "it never needed to come to this". No, it didn't need to come to involving a lawyer. We could have been good Americans and gone back to the US without our money.
We settled, only because the lady was a bag and was ruining our last weeks in the DR. We got most of our money back, and, hopefully, she won't do this to the next Americans who rent. We know people who have had personal dealings with her before that were not quite "right".
I will add that, other than divorce, this is the first time either my husband or I have had to get an attorney for anything civil.
So, I would suggest that you get an attorney. The cost is not that much in the DR, and we were told that most renters will give in if you fight. If you are in the Sosua area, I will be glad to give you the info on our attorney. Good luck
Mainer