"...Where do I find out more?"
That would depend on what information you are looking for. If you are looking for direct information about your individual servicer, then you'll need to research them on their website or give them a call. Your specific situation is unique to you and will be unlikely to be answered by someone other than them.
However, if you have questions about servicers in general, then there are many places to find out some information. It's understandable that if your servicer changes, you may wonder why, and you may not really get an answer from your servicer.
The one site that is a good resource for many things is called Mapping Your Future. They are a non-biased site that offers information in financial aid, careers, college, and money management. For the purpose of this posting, I'm going to share a specific link of theirs: http://mappingyourfuture.org/paying/loanservicers.htm This has answers to questions about Direct Loan servicers that you may find useful.