Random high peaks of latency/ping (Tucson Area)

During the past few months i have had a sudden peaks of ping/latency, the problem is that when i play game or videos online i have sudden "disconnects" forcing me to refresh the webpage or re-enter the game. i have called support a few times, in which they were able to minimize the problem but it is still present.

MODEM = Cisco DPC3825

what i have done so far was to:

-reset the modem (a lot of times)
-Connected it via cable instead of wireless (did nothing)
-Moved the modem closer to where the laptop is.
-Changed the Wireless Standard Channels to those with Acceptable interference
-Changed the Wireless security mode to WPA2-Personal (in my opinion this helped quite a bit)

Everything else was done by the Support Service.

After this, the problem was still occurring so i decided to test it with another laptop/device, and it appears the problem is withing the modem/service because all that devices that i tried  had the same problem.

 here is the test i usually do to check how my ping is doing. the left one shows when i am not using any applications that are connected, and the right one its when i have the browser or any games open.