Serious lawsuit problem being sued for $107,000?

ok i opened a credut cardin august or 07. i had been paying my mom monthly to pay it off. i had no idea she wasnt paying it though. so long story short she hid all the bills from me and i had no idea since i had stopped using that card anyways. i recieved a court summons in the mail from a collector saying i had to pay the money or go to court. so i got set up on a payement plan and they told me to disregard the summons because i was all set. so yesterday i got another letter from the court saying capitol one won on my default for not showing up to court $107,000 dollars. how is this possible and who do i call to get this resolved. i was told by the collection company hired by capitol one not to go that it would be taken off. im so scared. im only 19 and dont even own anything to my name. since i didnt show up do i owe them that and if so how am i suppose to pay it. HELP!!!!