I am having trouble with the co lines on this system. Sometimes callers are being dropped and then sometimes it sounds like they trip ring. I have loaded a patch but that did not help. This system is about 5 months old. I can't change out the Bcm without buying more keycodes can I? I need some advice before the customer hangs me..lol!! Is there anything inside the BCM that I can change out like a trunk card or something?