Essentially, I went on vacation for a week and my internet no longer exists, and a new, slower, but free wireless network popped up.

So how do I get my internet back?

Are we supposed to use this information, or are you trying to allude to an earlier topic? Could you post the link if that's the case?

Information is as is. I guess I could be more specific.

I left on July 1st, and my internet renews on July 2nd. I left my internet running to see if anyone was going to tap into it, but by the time I got home (July 7th), internet service is nowhere to be found, but a new insecure wireless network named "MyWLAN" popped up.
After I unplugged both router and modem, I noticed that the internet was still running, so I ruled out the fact that it was being hosted with my internet.

Speedtest tells me that the speed of this internet is one tier lower than the tier I actually purchase.

3m/256k vs. 10m/1m

Although free internet is great and all, I'd still like to get back to my other internet service. Haven't been able to actually establish a link with it, so I have a feeling its down... or something.
Going to be calling the company tomorrow, but I'd just like to have some insight before I do so.

First thing you do in situations like this is access the router and check what it says.

1a) If your router also "downgraded" your Internet then it's likely your ISP changed something. Call it and ask about it.
1b) In that case you can still try setting the router back to factory defaults and repeat the installation steps. Make sure you have the necessary data (usually a registration code) from your ISP handy before you do that, or your Internet will be down until help arrives.

2) When your router still displays the old Internet speeds you know its a Windows problem. The solution should be as simple as deleting all connections in the Network Connections menu (or w/e it's called in English XP/Win7) and rerunning the Internet wizard.