migration partially done

hello! We just switched to you and we had 4 users to migrate but 2 of them has over 10,000 emails. (not much though). However, after the first migration has been completed, one user has only 2000 or so emails migrated, and the 2nd user has almost nothing migrated... Now, everytime I start migration, it migrates only 200 or so emails... What should I do in order to migrate the rest. Very urgent because my old service is up to terms.

PLEASE HELP!!!

Leonard