It is not that simple to do. You can no just state you dispute all entries and think they are going to spend time and money contacting all of your creditors to validate the debt.
They (the CRA's) have a set way of disputing entries as listed in the FCRA. You have to dispute each entry and explain why you are disputing (debt not mine, incorrect amount, I paid allready!)
Here is a sample letter:
Your City, State, Zip Code
Name of Company (experian, equifax, trans-union)
City, State, Zip Code
Dear Sir or Madam:
I am writing to dispute the following information in my file. The items I dispute also are circled on the attached copy of the report I received.
This item (identify item(s) disputed by name of source, such as creditors or tax court, and identify type of item, such as credit account, judgment, etc.) is (inaccurate or incomplete) because (describe what is inaccurate or incomplete and why). I am requesting that the item be deleted (or request another specific change) to correct the information.
Enclosed are copies of (use this sentence if applicable and describe any enclosed documentation, such as payment records and court documents) supporting my position. Please investigate this (these) matter(s) and (delete or correct) the disputed item(s) as soon as possible.
Enclosures: (List what you are enclosing)
You will need copies of your credit report to highlight the items in dispute.
Hope this is of help to you.