Connectivity with internet goes up and down, up and down! Very frustrated.

I just got a new replacement gen5 modem because the previous one stopped working. I figured out how to install it myself (with the directions of course). At first, it just didn't seem to want to work at all, even with the lights on, I couldn't connect to internet, it was saying "no devices connected" on the state code. The next day it changed to the transmit and recieve lights on the modem were out, so coudn't connect then. Later that day my power went out suddenly for like 5 minutes. When it came back on, all the lights were on and the modem seemed to be functioning fine, I was able to connect my phone and my laptop, along with my desktop which has the modem connected to it.

Fast forward a day or two, maybe less, the modem lets me connect to the internet whenever it wants and then gives me problems connecting for awhile, running the system test, I got either the state code message 12.1.9 A transmit problem has occurred, or (and mostly) ... well, I have to wait for it to do it again since it is cooperating kind of right now, except I do have the 12.1.9 code going on atm.

Anyway, as I was messing around with everything trying to fix it, I ran the connectivity test also. After awhile, it seemed that each time I ran the connectivity test, it would put the the state code section back to green and all's good type message. Even if the connectivity result was that I was having limited gateway connection (something like that), then it would all turn green and I could use the internet for a bit...except...for my phone and my laptop. My phone would connect to the wifi and say "connected.no internet". Every once in awhile it might let me connect for a few minutes. My laptop seems to be halfway connected, with half pages turning up on the net, then showing that page that says something like "check your internet connection" "run network troubleshooter" (again I am just paraphrasing).

Now I live on a small mountain, so my phone gets pretty crappy reception, like 1x, if I can even get that! Lots of times, depending on where I am, I have no reception. Sometimes I will just leave my phone out in the mudroom and run the hotspot just to be on the internet when the modem decides to be jerky. It brings me back to the good old days of dialup modems with the "quickness" of it. Haha! 2400 woohoo.

This is really irritating to me, and hopefully somebody here can help, because calling tech service is not convenient for me, as I can't always be sure I have all the time I need to get things done (or not done, as it sometimes happens).

In the meantime, I guess I will just keep clicking on the connectivity test to try and keep the internet connection going. In case you are wondering, I have rebooted the modem, I have unplugged the modem and plugged it in a different socket, tried it with a surge protector strip, the outlet on the wall (where it is now). I just don't know what else to do, except post here. If this doesn't work, calling tech support is my next option.

I really appreciate anyone who takes the time to help me out, I work better off the phone than on. So thank you in advance for any help and I hope I didn't ramble on and make it difficult to understand what I was trying to say. Oh, and I will add that other state code when it happens again. I will try to get to this post to check for replies as often as I can and as often as it will allow me! 

Have a great day everyone! :womanwink:

UPDATE: Here is the other state code that I usually get, I get this one the most: