penn foster worse mistake ever Internet

i enrolled in 2006 for online course in Vet Assistant, oh i was too excited and could not wait to start this course , well i got my first package of books from PF and i begin to study right away, and continue to do online quizzes and test, well after maybe the fourth test or so, the material was no longer coming as promised, no one ever returned my emails and i have never spoken with anyone there, thou i tried calling again and again, would leave messages, no return calls, so i just waited and continued to study the material in which i had recieved, by the time i got to taking test number eight, i had not recieved any new material, so i cancelled out, to my understanding you had to complete at least 10 or more test, to continue in this course, and you would not be obligated to pay for courses you did not complete, i ,too recieved a bill for over 300.00, which i down right refuse to pay, it is now on my credit report, i have tried to contact PF, no one returns my calls and i can't seem to send a email because i am no longer a student..i have disputed this thru my credit report, but it's still there and i ain't gonna pay them s**t, the experience was the worse ever, sometimes you could not even log on as a student, i am just waiting to see how this turns out in regards to having this removed from my credit report, but i advised anyone and everyone to avoid PF as if your life depended on it, they will ruin your credit without a blink of an eye..they stood not behind any of their promises of support...they are a rip-off to every degree