Ok,
I can still be the same problem over. If the phone cuts out, it could still be because the PS4 has a static address which conflicts with the phones address.
Check this link out. It's for a linksys modem but the fundamentals should be the same.
You should be able to check what device is assigned what IP address from the modem menu. If you see that the PS4 takes the same address as what the phone use to have, it's a good indication that there is a conflict.
I had a static address for my PS3. What I did in that case is I put the address very high so that the dynamic addresses would not conflict.
http://portforward.com/networking/static-ip-ps4/
Might want to talk this one true rather than "emails"
Pat