slow internet since yesterday

Since yesterday Xfinity internet speeds are 100-220Mbps - i'm paying for 1.2Gbps. Its up and down, speeds varying all the time. 

Support is terrible, bunch of scripted responses, constant asks to how my day is vs. fixing the issue. After 30 mins of diagnostics, support tried to sell me another Xfinity modem asking me to pay more monthly.

So Xfinity you can't deliver service quality or admit to a network problem on your switches but then try to sell me new equipment promised to me for free in the first place ?