Business line bandwidth, how to know I am getting what I paid for

We are a school district in very rural alaska, we pay quite a bit of $ for our bandwidth. My networking skills are good for lans, but basic for wans. So we have 10 sites with x amount of bandwidth per site. Our biggest site has 100 mbps symmetrical. But we get lots of complaints of slow internet. When a complaint is made to the isp they refer to netflow by solarwinds, showing us that the bandwidth is not maxing out. Even Though they admit that those metrics show an average, not actual bursts. My question is,

1. how do organization know that they are getting the bandwidth they pay for all the time?
2. Is there a way to monitor the network including bursts to know that I am getting the bandwidth I paid for?
3. Will using a cloud based BGP, so my ISP just delivers my bandwidth to the cloud for routing be a liable solution?

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I am open to suggestions or comments, thanks in advance.