sprint chargeing me for a broke phone i left at store orlando, Florida

back in oct. 2012 my husbands htc evo from sprint broke. we took it to the waterford sprint store location in orlando fl. they said they would look at the phone and to come back in an hour.

so we went back to the store the sales rep had said that he had to order us a new phone. he then handed me the old phone back i asked him what i should do with the broke phone he then said i would need the battery from the phone to put into the new one that was being mailed to me. i could either leave the phone with them or throw it out.

i then took out the battery and left the phone on the sales reps counter.  its now december 2012 and my father gets the sprint bill they are now charging us 350 dollars saying i never sent them the broken phone. 

i spoke with a sales lady for two hours useing the *2 on my phone she spoke with her manger on december 16th they had told me they put in the notations that the price for the phone was to be taken off. 

i was then put thru to technical support whoms manager told me the price for the phone would be taken off my bill within 24 hours well its three days later its still there.

i call them again spoke with a different manager whom is telling me without the phone they cant take it off my bill and the sprint store is stating that i never gave them the phone when i left it at the store on the counter infront of them.

so know i am lost for words to find out 3 diff mangers one being a superviser on monday said sorry and it would be off my bill to find todays manager basicly called them liers.