Since this has to do with a debt that has been disputed by you, the number of days you have to send this letter is 30 days.
Following the receipt of a phone call from a debt collector concerning a debt that has been disputed, the next action you must take is to write the debt collector a letter within 30 days after the initial contact.
After then, the debt collector must stop all collection attempts until the appropriate verification is acquired.
Learn more here: https://brainly.com/question/25919625.