Address Location

Why does the IP addresses constantly changes from the same scammer.

Good question Dimples. How it's been explained to me is thus:
It's probably how the individual is connected to the internet. If your scammer has been assigned a static IP address by their ISP, then probably you would see only that IP address when it connects to the internet.
More likely is what's called a "dynamic" IP address. That means the smammers ISP will automatically assign an IP address to it's computer each time he/she connects to the internet. That IP address could be the same from one time to the next, or it could be quite different. Apparently it's completely at the whim of the ISP's networking equipment.

Sometimes it is due to a dynamic IP address, but often it is even simpler than that. Many of these scammers do not have their own internet connections, so they use internet cafes or other businesses offering internet access. In areas that are heavily infested with internet scammers, there may be dozens of these in a very small area. Each one may be set up differently, and each computer will have a different IP address. Some of these businesses that cater to scammers may also have computers running through proxies or use other location-concealing techniques (often they charge more for use of these computers). From one day to the next, or even at different times of the day, the scammer may change computers or even locations if the cafe he prefers is full, and his IP will change as a result.