Allied Interstate making constant calls

Send a cease and desist letter to their mailing address. Under the fdcpa laws, it will be illegal for them to continue the calls after receiving your C&D letter.

Keep a check on your credit report also if they are putting any inaccurate item. This might hurt your scores.

I would at first send a partial cease and desist letter (return reciept) stating that you'll only be communicating in writing. If they call after getting your letter, it's just one more ground for suing them.

Send them a cease and desist letter via certified mail with a return receipt request. Keep a copy of the letter for your record. Mention in the letter that the collector should cease and desist further communication with you. Send the letter within thirty days of the first contact by the collection agency or collection attorney. Once the collection agency receives that letter they are allowed to contact you only once via e mail to notify you their intent.