Sprint Wireless Airwave Cancellation Fee Scam! Internet

I had a problem after I moved with poor reception on my Sprint cellphone. I called customer service to see if I had any options, i.e., getting out of my contract. I had 4G at my old address and the new address not only lacked 4G, but only had 2G - with only one bar on the signal indicator. The Sprint representative advised me that I would be charged regardless if I cancelled and that I should try their Airwave device. She told me that I wouldn't be charged for it, and shipping was free. I said sure, "I'll give it a try." 

It arrived about 4 days later, and I hooked it up to my internet modem - why it needed access to my internet modem I have no idea. Well, after 2 months of "trying" I gave up on it. It only marginally improved my signal - if I placed my face on the window like a fish trapped in a fish tank. After weighing my options I decided to cancel my service after being with the company for 2 years. About a month later I get a $220 cancellation bill for the Airwave. When I read the bill I about jumped out of my skin. Why was I being charged? It must have been a billing error, so I called Sprint to rectify the situation - their error.

I spent about an hour being transferred from agent to agent, ultimately hung up on. I called back - more of the same. Finally, I got to a supervisor who said, "didn't you get a letter saying you agree to a 2-year contract with a $200 cancellation fee if you terminated early?" I was dumbfounded. "No." I said, and I went on to explain the situation. The supervisor said he'd have to call me back in 4 days - yes, 4-days. He said he'd have speak with another department to see what he could do for me. I'm like, "see what you can do? This isn't my problem. Why should I have to wait 4 days for this error to be fixed?" He mumbled about for several minutes, and said I'll talk to you in a few days.

I have NOT heard back from them. These people are trying to scam me with a fraudulent fee, which I asked very explicitly at the time if there were any "fees" associated with it. I was assured several times about it. I'm left to fight them on my own here. What am I to do? I didn't agree to this, nor did I sign anything stating I would agree to it, nor did I say anything verbal. I'm so tired of companies like Sprint shamelessly signing their customers into contracts they are not aware of. Has this happened to anyone else? If so, any advise? What legal options do I have? Any help would be appreciated!

NEVER trust sprint or their Airwave devise. It used my internet connection and they had the nerve to charge me? Where is my money for piggybacking off my internet that I pay for, Sprint???? SCAMMERS! Consumers beware of their shady, unprofessional business practices! Where are your morals?