Great Lakes Student Loan Complaint

Great Lakes Student loan department,

Non-federal student loan Dealing with my lender or servicer Having problems with customer service Texas

I graduated in - 2014 from the University - after living in - for 20 years, and then relocated - in - 2014. I updated all of my address changes, but never received any communication from my student loan debtors until yesterday when I received a phone call from a collection agency demanding payment. They want me to make - monthly payments in order to get my loan out of default. I had NO idea I was in default and feel I have done due diligence in making a good faith effort to remain in compliance.