Mortgage company?

So my mortgage was recently sold from chase to Carrington mortgage company. I received a letter in the mail stating this change, never received an invoice or bill or anything was told I could call in but it is a 15.00 fee or I could pay online for free. I got online and went to their website and was told I couldn't register until 10/6/15. So I got online tonight just to check since it's due the 1st and it says there is a problem with this loan. I plan on calling in the morning but I'm so worried I read so many bad reviews:( why couldn't chase just keep my loan ugh. Has anyone dealt with this company before?