Hi Susana
If both mirrors were fault free before this then there are two possibility of whats wrong firstly one of the mirrors is faulty and causing both mirrors to fold back out or one of the modules that controls mirror folding inside the doors is faulty.
I would try the mirrors over the next week or so because some times the mirrors can play up intermittently and then all of a sudden start to work ok again.the mirrors have motor in each one which sends a signal back to the modules and once the module receives this signal it stops the motor in the folding in position if the module does not receive the signal or it is faulty the mirror will fold back out.
Regards Steve
BMW Technician
city & guilds - Bmw Senior Technician