What happened to my 700mb download speed ?

I have been enjoying 600 to 700 mb download speeds for the past year. now for the past 24 hours, I am in single digits and the teens.

Was on with support and they actually had me go to the store and get a new modem suspecting issues.

Long story short, no tower issues, no throttle, nothing new added to netwrok and new modem. I am only maxing out at 27mb. what happened? 

I am out here in brush prairie wa.

anyone having similar issues ?