I played this game with our local connectivity provider.
They used a wide variety of dodges to avoid coming out to fix the issue.
Ahh, but when they finally came out, what did they find?
Good question, and you perhaps won't believe it...
The buried wire was the ORIGINAL phone line, installed in the 70's or 80's. The wire developed a break in it. The local phone 'engineers' spiced the line, and mounted the splice in a box on another pole that was installed, apparently just to hold the splice. The local carrier started replacing their main hard wire runs with buried fiber years ago, and finally didn't need the copper wiring, so they started removing it and the support poles. The grunts that removed the wire and the poles found the splice on that pole, and just ripped it off the pole and threw it on the ground. Really... So we get DSL, and the service has to have 'bonded pairs', with some degree of uniformity between them. The 'modem' showed massive fails on one pair, and a few on the other. Our service was up and down like a grasshopper. Our VOIP was down so much our alarm system was alerting it several times a day.
But it gets worse.
The tech that finally came out was amazed that the line was working at all. He decides to 'walk the line', and finds the splice. There is NO record of the spice existing in any of their records. Hmm... The splice is found under several trees and other brush that had been cut out by the brush clearing crews the carrier pays to maintain the right-of-way. The spice is not weatherproof either. They pull a new line. It takes two weeks to get it buried. The problem abates, but is still there. The connection from here to the DSLAM is golden, and from there to the head end is golden. It's the card in the DSLAM. Well those cards are upwards of $60,000 each! It takes MONTHS of calling and emailing logs to get someone to FINALLY admit that the card is bad to, and another month before it's finally swapped. Guess what? Things are working well.
But I was given stories about the fluorescent lights in my basement causing the problem, the firewall I have causing the problem, the gauge of wire I had from the demark to the firewall causing the problem, power interference causing the problem... They tried every lame excuse for the issue, and it turned out to be 100% their issues, and their historical incompetence magnified over the years.
Yeah, if you can connect to the modem from the inside, yet can't connect to the outside world, I can say with a very high degree of certainty that it's outside issues that are causing the problem. Heck, the carrier even tried to charge me for a replacement modem, until the replacement rapidly showed the same symptoms. Carriers don't want to do anything that involves sending someone out to physically do anything. That is why AT&T is pushing DirecTV! No wires, no local techs, no expensive testing equipment. No happy customers either.