i haven't read much of this thread, but you need to tell your parents NOW. They need to be able to dispute these charges immediately. Preferably before the charges even make it to statement as then you avoid the hassle of finance charges, etc. while this all gets straightened out.
call the cc company. say you (cardholder) did not make that charge. you should be off of the phone within 5 minutes. I've dealt with fraudulent cc charges many times in my line of work.