Any idea how to clear up static on Bluetooth Link2Cell handsets?

[AC Question]

I'm using a Panasonic link2cell cordless phone system linked to my Samsung Galaxy 7. Recently the call static on all of the 4 handsets renders them almost unusable. There is no corresponding static on the cell phone itself. I no longer have a land line. I use the cordless phones as "extensions" throughout my house for convenience. They are plugged into electrical wall outlets. Any idea how to cut the static? They do not have a means to select different channels on the phone. There is a noise reduction button that has no effect.