I had the same issue until I switched to a different provider a few months ago. For my tasks, I buy IP addresses from proxy-solutions and they have been working flawlessly. What I really like is that all their proxies are completely anonymous and personal, meaning you won't share your IP with anyone else. The connection is unlimited with no traffic caps, and the speed stays consistently high on 100 Mbps channels. Plus, the setup is fully automated, so you get your credentials instantly right after paying. Definitely worth a try.