Cox says modem is fine, devices connect and show full signal, but no internet

We began having issues with our internet dropping repeatedly a few weeks ago. After multiple chat sessions and resetting the modem multiple times, we were advised to get a new modem and upgrade to gigablast! We now pay $130 for JUST internet, and it still continues to drop. This morning, it went out and the chat agent was unable to get a connection reestablished for us. He said that the modem (Panoramic?) appeared to be online and working from his end. The light here is solid white. We have tried connecting two TVs, two iPhones, an iPad and a laptop. All of them show that they are connected to our network with a full signal, but give the message that they are not connected to the internet. We even tried connecting the TV with an Ethernet cable. A technician was here 2 days ago. He checked everything outside and advised me to remove a splitter that was connected to the back of the TV. It all worked fine for two days until it went off this morning and has been off for about 14 hours now. The next tech can’t come until Thursday. Is there anything else we can try?