Network appliance that constantly monitors connection speed being delivered from ISP

I live in the country and pay a ridiculous amount for a slow connection speed. I work from home and am often on long videochats. I frequently have to troubleshoot speed and latency issues with the equipment at the house and then contact our ISP who nearly always denies there are any issues. Are there any network appliances that I could plug in between the modem and router that would consistently, or at a specified interval, would perform a speed test? I think I could build a device and add possibly configure a cronjob to do this but figure there has to be something on the market already and would prefer something that I would be fairly maintenance-free. Don't want to just add another layer of troubleshooting.