MCI Collection Fraud/non customer Dallas, Texas

This will be the second time I have received a fraudulent bill from MCI.

I have never been a customer of theirs, however about 5 years ago they sent me a bill from a collection agency stating that I had a delinquent bill that needed to be paid.  At that time I proceeded to call them and have them send me detailed billing information.  It happened that the land line phone service was supposedly set up in my name at an old address approximately 4 years after I had moved away.  I disputed it, being able to prove that I was not present when the billing was set up, and no social security number was acquired by them at the time of set up.  They left me alone, end of story, or I at least thought so.

Now....here currently I have received another collection bill wanting me to send my payment direct to MCI, Dallas Texas.  This time I will not ask for billing details, because this scam is getting real old.  I have moved twice since the last time, and I'm assuming that they will show me setting up an account with them at my previous address, beings how I'm pretty sure that this is how this scam is ran.

Either way, I will be sending them a conformation certified letter disputing their false charges.  I will also be awaiting MCI and mines 5 year anniversary collection date in 2015........I hope they at least get me some roses next time.......

Anymore advise would be appreciated, I want to end this unwanted MCI relationship.