If your alarm is under warranty, it is best to check with the supplier who holds the warranty to ensure that the warranty is not voided by having someone other than the initial installer servicing your alarm. If the equipment is out of warranty, then you have the choice of using whomever you wish. Also ask your technician for the master code for your alarm, as in the future you may wish to use a different company to work on your alarm and this is information they will require for programming.