Recommended tools/approaches for continuously monitoring my flaky ISP?

Lately my internet connection has been going offline for a few minutes at a time several times a day (like, 3-5, minimum). Most of the time the ISP doesn't acknowledge anything is going on, and by the time I get on a phone call with them and wait on hold for some mindless drone to answer the phone, the connection will be re-established.

If this was only once in a blue moon it wouldn't bother me much, but this has been a daily occurrence now for at least the last 3 weeks and it's driving me nuts.

So before I contact the FCC - because that seems to be the only way to cut through the hordes of mindless, clueless idiots who try to block your ability to talk to anyone who knows what the hell they're doing - I'd like to have some proof. Some log data that shows the connection dropped offline at time X and came back at Y.

Now, I could try to build something like this myself, but before I do that I'd like to ask here: is there already a well-known, widely recognized/respected tool out there that does this? Bonus points if it's something my ISP (Spectrum) is likely to be familiar with. Imagine how they'll react if I tell them I wrote my own code that proves the service has been unreliable: "well, it must be your fault". But if it's something they've heard of, they'll be more likely to take the data seriously.

Thanks for your suggestions.

(Oh, and if this is a "just google it" sorta thing, what do you call this kind of tool? "Network Monitoring" is way, WAY too generalized a term to be useful, and I'm not sure what else this might fall under.)