Have you tried unplugging them from the phone lines and their power source for 5 full minutes?
Please thy that and let me knwo if that clears the issue?
This could be a phone line issue, since all the phones are seeing this line busy condition.
If this doesn't clear the problem, try connecting one phone at a tiem see if you still have the busy condition, if so, then the phone provider is to blame and they need to fix the lines. If it still gives you trouble with only 1 phone hooked up then the phone is at fault.
I will send you an offer so we could talk on another phone line or a cell so I can help you better.
Let me know if you want that service?
In any case, I will stick with you until this is complete.
Please rate kindly thus far, it won't cost you anything to rate my service to you kindly,
There is NO cost to rate Kindly;-)
But it is the only way I am credited for my time and expertise in this field.
Then you can reach me by simply replying to this message anytime.
Thank you and have a nice day!
If not thats ok too;-)