sprint pcs BAIT AND SWITCH - TRYING TO SCAM ME OUT OF $525.00 !!!! Overland Park, Kansas

I signed up for Sprint's so called, "UNLIMITED USAGE" plan... i was told that i had FOURTEEN (14) DAYS TO CANCEL and receive a FULL REFUND.. NO QUESTIONS ASKED.. Four days later, i receieved E-Mail, telling me i had GONE OVER my USAGE LIMIT, when i was told i had an UNLIMITED PLAN... i had paid them $53.00 when i took out the service.. for ONE MONTH..

This E-Mail said they were now charging me five cents per mega byte of usage.. i IMMEDIATELY replied, telling them i had NOT signed up for ANY kind of service that had any type of LIMIT of usage, and that i was CANCELLING IMMEDIATELY, and that i would be taking back their plug in modem thing the next day, and expected a full refund... and that i was CANCELLING this service immediately...

As soon as i sent that E-Mail, i unplugged it, and put it back in the box it came in.. The following day, i took it back to the store i had gotten it from, and they refunded me my $53.00 right there and then... 
 
 Their representative (at the store) assured me that we were SQUARE, and that i had the RIGHT to CANCEL this, and that he understood it just didn't work out.. and he was polite...  i left there satisfied, that i had gotten my money back, and that maybe sometime in the future, i might consider using them again... they had proven true to their word...  yeah, right...

TWO MONTHS later, i get an E-Mail from Sprint, warning me that if i didn't pay them over $525.00, that they would turn me over to a collection agency...  $525.00..?  WHAT $525.00 ??? They have NOT DENIED that they have gotten ALL of their equipment back, or that it was in good condition.. they are simply trying to SCAM me out of $525.00 ....!!!

Other internet providers charge LESS than what Sprint says they charge per month, and it is for UNLIMITED SERVICE...  so WHAT is this $525.00 about, for FOUR DAYS of USAGE...??  i am going to get a CLASS ACTION SUIT going against Sprint.... i was astounded, to find over 2550 COMPLAINTS against Sprint on this forum, when i first typed in "Sprint"....  HOW CAN THEY KEEP DOING THIS, AND NOT BE SHUT DOWN BY THE FEDERAL TRADE COMMISSION..???!!!