LoL disconnecting repeatedly but internet is still working??

For the past few days, League has been constantly disconnecting and connecting in game every couple of minutes, to even seconds. I've tried all the technical support steps and even the Hextech Repair thingy. After reading on some other peoples' discussions from past posts (like a couple of years ago), I feel like it's my ISP (Spectrum) problem.

I have no clue how to fix this. If even it is their problem.

Plzz help.