AES/PHEAA Student Loan Complaint

AES/PHEAA Student loan department,

Non-federal student loan Dealing with my lender or servicer Don't agree with fees charged Florida

I started my private student loan with - bank and then I get a letter stating they are selling my loan to AES. I never signed any paper work with AES and now they want to raise my interest. I had to go through extensive work to obtain a loan with - and now it can easily be passed over to AES? I need to have documentation stating that I 'm OK with that and need to have my signature on AES paperwork.