Battery life problem with wireless sensors

Hi, we experience a battery life problem with our wireless sensors.
We have to change them every 1 or 2 months and are far of the 1 year life announced.
Any idea of what could happen ?
Regards

When did you purchase the wireless sensors? and also what is the specification of the battery you purchase every 1 or 2 months?

We purchased them in December 2014. The batteries are CR2450 lithium models.
We use to have frequent disconnections of all our wireless sensors (10) with the sensorgateway. Does that connection problem could be at the origin of the battery drain ? If yes, is there a solution to stabilize the connection ?
Here are our device informations : Hardware Version : Release 5.0 / Firmware Version : Release 5.07 / Build Date : Jul 3 2014 / Interface Type : RS232 / Product Name : Temperature & SensorGateway.

please update your firmware to the latest one http://www.serverscheck.com/support/firmware.asp

regarding the batteries it might have been the batteries itself and not the sensors and regarding the wireless disconnections it has the same factor as being disconnected to a wireless router if you have walls, electromagnetic devices near the vicinity etc. though having the latest firmware would help with the connection.