High latencty issues.

From past two dayz im playing with 350/750/1500/2500/3500 latency which is absurd!
I had a lag spikes from time to time, but it was a spike...
Called my internet provider - they fixed whatever they think was the problem from their side - yet, still my latency is getting worst and worst....
P.s. - my internet speed is 300 Mbps

I have the same problem. There was no problem until a few days ago (stable 60ms) but now it doesn't go below 150 ms.

I have been having same issue with constant DC and tells me a character with my name is already logged in. At one point my lat hit 12.5k and I'm hardwired to my router.