No info given to me at all

I upgraded at ALETCH AUTOPAGE MONTANA . i was not told that i was stil going to pay my old contract becuase i was called that i can come and upgrade my phone so now they took n debit order of almost double the amount that they should because they think its funny or something i was NEVER told that i still have to pay the old one becuase then i would have upgraded and now i really upset becuase i have n small baby girl and i mange my money to the cent and now they took this money and i can not do anything , i went to then on saterday morning and they were only rude to me and told my but you are goint to anyways pay it if its now or next month and this is completely unfair i dont know waht im goint to do now please can you guys help me i would appreciate it