Yeah, I also only had issues with one servicer. I never had any problems with Direct Loan.
However, in addition to handling the transition poorly, I had other problems with Great Lakes. When I would send payment amounts over my monthly payment, as a servicer for federal loans by federal law they are supposed to apply extra payments to your highest interest loans. Of course they were not doing that for me. When I called about it, they said, "oh, you have two separate accounts, so we split the extra payment between the accounts." Umm, no, I only have one account number. "Yeah, but there are two accounts within the account." How can I distinguish between the subaccounts so that my payment only goes to the account with the highest interest loans? "Oh, just write the name of the loan type on your check." That doesn't sound like two separate accounts to me . . .
It took me three representatives to get to somebody who would assign numbers to the subaccounts. Even so, she still recommended sending separate checks: 1 for my monthly payment, which would go towards both subaccounts, and 1 for any extra, on which I wrote the subaccount number for the one I wanted my payment to go towards.
All this runaround, just to get them to do what they were legally required to do anyway.