Paid collection still on my credit report. How to remove

I was looking for someone to help me and give me advice and I found your site. I realized that I screwed up when I paid in full the debt I owed to LTD, a collections agency. I paid through an electronic check and asked the person helping me, "So I'm all done right? There is nothing or bad on my credit report?" And the guy said "NO, You're all fine." Later on I tried to raise my credit limit and my bank says that I have something bad on my credit report and its going to be on there for SEVEN years!!! I have been trying to call the collections agency but I just keep getting transferred to like a million people and I have called so many times. I really need help because I'm only 19 and I don't want to have something bad like this on my credit report. I need a new car to go to school and there is no way that I could get one now that I have that on my credit report!
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nothing you can do here
but
1) dispute the account and hope
2) wait two years for the accont to not hurt your score as bad
3) keep at least open lines of credit for at least 12 months to over ride the past bad credit

remember you paid the bill ad in the end that is always best. It over and its done. It will only hurt for 2 years. 5 of those years the account is irrelevant if it is paid and you have new good credit.
AND
there is no gaurantee that even if you negotiated before you paid that they would agree to remove the account completely.
So do not beat yourself up. go on and remember