What's up with region 8?!

I have been playing this game for a few months now. Very challenging and entertaining. I did't think i liked any hunting games untill I tried this one. I have reached region 8 and already conquered it, with two pieces of the map. Since then I've just been building my bank. I'm a level 45 hunter with over $100,000,000.00 in the bank. Now I've been kicked back to region 7 and can't seem to advance. Am I being forced to use my credit card for better weapons to advance to a region I was already on? Please explain? Thank you.
Super Dave