Rental contracts in Mexico are only legal in Spanish. If you didn't understand what was in there, the onus was on you to ask for a translation before you entered into the contract. Some contracts DO provide for 60 (or 90) day's written notice to leave early.... some with circumstances spelled out, others simply that provision.
Everything Alan said was correct.... with the exception of the fact that I've been here a LONG time and have never once heard of anyone getting a security deposit back. (1) Money has already been spent. (2) Unless you have a video of entire home on day of entering, and again on departure, you can be sure there will be "things" found that needed repair on your exit........