Modem continually sending data back to base

[Phil]

I know this has nothing to do with Ubuntu but I'm at my wit's end and 
someone may have had the same problem and found a solution. I have 
scoured the Internet for a solution and all that I've found is this is a 
common problem.

I have an old Nighthawk M1 which works well except that it continually 
sends data somewhere, presumably back to Netgear.

Openwrt doesn't support this device so that option is out.

There is a black-list setting which might be used to block nighthawk 
analytical. That looked promising but so far hasn't blocked data sending.

I can use my old phone as a hot-spot (it's slower than the Nighthawk) 
but because of the phone's age it will be blocked from the network in 
February, so now I have to go phone shopping.

Any suggestions at all will be appreciated.

-- 
Regards,
Phil