We, like many of our friends, had our landlady increase the rent by 50% and we are forced to find other accomodation. In order to protect ourselves in the future, we were advised to get a legal rental contract.
We found a sample fillable form at

https://www.wonder.legal/mx

called a "contrato de arrendamiento por temporada vacacional"

After you have filled in as many details as possible, it costs $99 Pesos (about $5.00) for the download. It is still possible to make changes once it is downloaded.
Next, go to the rental property and make a list of everything that comes with it and note that all the appliances, ceiling fans, etc are in good working order. Photos will also help.

Make 3 copies in Spanish, 3 co[pies in English.The list and photos become addendums to the contract and must also be signed and witnessed.
All parties must initial each page and sign their legal name on last page. Delagaeo will witness and sign in his official capacity as mayor with an official stamp. One copy of the contract in English and one in Spanish is kept at the Delegado's office; the other copies are for the landlord and renter.

This contract will protect your deposit (copy of receipt to be attached to contract). This protects your money in case things are not in good shape or are missing when you arrive and will prohibit any rent increase during your agreed upon length of stay. (Note: A new contract needs to be filled out for the following year.)

If you would like more info, email me
myrandaobyrne@gmail.com