Mr Cooper Mortgage Co review: Escrow account

Lakeview/Mr Cooper took over my mortgage loan servicing and I am now told that my escrow is short over $800. They are raising my monthly payment by $100. I checked with my taxes and they went up only $115.16 for the whole year and insurance went up $475. a year. Which puts it at $590.16 over 12 months that is only $49.18 a month. How can they raise it double that amount. What happens to the escrow from my previous mortgage company? Isn't that transferred over?