(Others have given the answer while I was typping. It is of course dynamic IP. I decided to post this anyway as it is a bit more verbose way of saying the same thing with a bit more info for noobs.)

If you are on a dial-up or a DSL modem through an ISP, your IP address is most likely dynamic. You can check your current address by visiting one of the many "what's my IP address" websites.

The address you will get is the address of your router. As far as the Big Bad Internet is concerned, the IP address of your router is the IP address of all computers behind that router. (Most routers allow you to check the outside facing IP address without having to use any external services).

By switching your router from DSL to your phone (presumably 3G or 4G), you have changed the ISP and of course your IP address has changed.

Regarding the ban, it is a sad state of affairs that many services impose similar bans far too quickly and far too easily. You got this IP address today. You may get the same one tomorrow or a different one. Someone who had it yesterday, last week, last month or last May, was doing something that website did not like and now you suffer. It may be even worse: the service may have banned the entire range of IP addresses provided by your ISP, because your ISP has a reputation for hosting spammers.

There is next to nothing you can do about it. You can complain to the service and ask for revoking the ban. You can complain to your ISP and let them sort it out. In both cases the chances are small. Your best bet is do what you have done, change the service provider. Even if just temporarily.