Spirit Airlines $9.00 club renewal, without notification or authorization Internet

When I opened my American Express bill, there was a charge for $59.95 from Spirit Airlines - Date of departure 12/31 - ticket #TEMHAR.  I checked with AE and they said it appeared to be a membership.

I joined Spirit Airlines $9.00 club sometime ago.  I do not remember when, but I did not join for the rest of my life.  I thought I was joining for one year.

I received no renewal notification or anything that would indicate that I was going to be charged.  I did not authorize this renewal and I do not think they have a right to charge me for something I did not authorize.

If the departure date of 12/31 is when I joined then why am I being billed on 7/28????

On Monday, 8/1, I wrote via e-mail to Spirit and received an automated response.  I wrote again on Wednesday, 8/3 and still have received no response.  I e-mailed them again today.  I tried to call them but got someone in another country, who I could not understand, and when I asked that I be transferred to someone in the US, I was told there was no office in the US, but today I saw on a Ripoff Report that they have corporate offices in Miramar, Fla.  

How do you get to them to resolve a problem. This is a very unethical way of doing business, and I would venture to say - not quite on the up and up!