It sounds from the description that you may have a signal problem with your network, preventing reliable communications between the PLC and the EZRain. Please check for signal filters, or other signal-attenuating devices such as surge-protected extension cords, etc that may be actually causing signal degradation.
If the unit is defective, then it is best to return it where you purchased it. We added some features to the firmware (version 2.0) to enable linking the EZRain to a controller such as the KeypadLinc. However, the version of firmware that you have works as advertised. Should you wish your unit to be upgraded to 2.0 firmware, you can write to us for an RMA, and then send your unit postage paid for us to upgrade.