The proxy provider usually keeps logs of who uses their proxies.
Generally, they won't give you those logs because you're a customer of theirs and they don't want you to know how many other people are sharing the pool of ips used by their proxies.
If your goal is to be the only person using an IP, you'd have to set up your own proxy software on a VPS. If you only want a few IPs in a certain country, you can probably get it done for ~$10-15 per month. But, if you're not technical, you may have to hire someone to install the software for you (which would cost extra).