Universal Credit Services, Inc Debt Collection Complaint

Universal Credit Services, Inc Debt collection department,

Medical Cont'd attempts collect debt not owed Debt was paid Michigan

Attached you will find a copy of the check written on -/-/15 to - - - which also shows clearing my bank account on -/-/15 for $250.00. Why am I still receiving harassing letters ( see attached dated -/-/15 ) along with a statement ( see attached ) showing a past due of $250.00? Universal Credit Services continues to say my complaint is without merit. They are attempting to collect on a debt that was paid several months ago which I provided documentation for. This is harassment and my next contact will be through my attorney. Why are collection agencies such as Universal Credit Services allowed to continued this type of activity?