I received A letter that my account had been turned over to I.C. Systems. I believe this collection attempt is in error, as it refers to a XXXX account that was closed in XXXX 2015. After the account was closed, I contacted XXXX after receiving a bill, and they informed me that their billing had simply not caught up to their emails, and that I owed nothing on the account. 
I attempted to contact IC System via their website and the phone number listed on their letter, but the website does not exist, and the phone number rang once and held.