Before you contact anyone about mini split run a HVAC load calculation (
www.coolcalc.com/ Its free) have an idea of size unit you may need. After you know what size unit you need then you can start shopping for units and I would choose a unit that uses inverter technology and has soft start for the compressor (variable speed) and the highest seer rating you can afford (energy efficiency) and R410 refrigerant (environmentally friendly and more efficient) . Check to see the min and max btu rating of any unit that fits your heating and cooling needs.
The reason for choosing inverter with soft start: Lets say its 77F in the room and you set the air to come on at 75F the compressor will come on on the lowest speed and ramps up speed gradually to get to 75F ( non inverter units comes on at full speed all the time and uses more energy)
The reason for verifying the units min and max btu range: Lets say you have a 1 ton unit (12000 Btu rating) and the room or house requires 7000 btu cooling and the unit you have has a cooling btu rating 4000 - 12000 then you will be running the unit below its max energy rating (saves on electric bill) and the minimum btu rating is what the unit will come on at then gradually ramp up (saves on electric bill)
As far as I know Muebles Coloniales is an authorized distributor for Mirage mini split they may not have the best selection or prices so you can purchase online or where ever you can find a deal and have the tech at Muebles Coloniales come an install and register the unit for warranty. Or you can install it yourself and no warranty and if there is an issue in the future purchase parts direct from mirage and install yourself.
There is also another HVAC store (Reincom refrigeracion industrial and comercial 638 102-0065 the owner speaks English) on Samuel Ocana Garcia pass the Autozone on the right
do not go to the one on the left
www.ecoclimas.com.mx/
They have good prices and they deliver