Did you upgrade to a completely different ISP, or just service with same ISP? In doing so, did they change out your modem as well?
It doesn't make sense that your connectivity issues are stemming from the server side. It makes more sense that there are NAT or open/closed port range issues within your modem preventing it to maintain a consistent connection with the game servers, or to other players online.
AT&T's equipment is notorious for this and causing online gaming issues. So, if you're with AT&T, I'd start looking in that direction. If you're not, it would still be helpful to look into and cross off the list of troubleshooting as this is almost always the cause. Some online searching may help you find what you could try whitelisting in your modem to help with the DC's.