If you are still searching for a provider, you may wish to contact "3Gstore.com". They sell systems for wireless access and I found them very knowledgeable and helpful when I was doing my search. Initially I tried using T-Mobile since that is my cell provider, but they could not make their system work. 3Gstore worked with me to figure out the best provider and made the system work. My contract has no limits and I've had access near everywhere we've gone.
The phone number for 3Gstore is 847-462-4004, and their email is "sales@3Gstore.com".