You should always ask for a hearing, even if you now have the proof your worker wanted. If your worker approves your case while you are waiting for the hearing, you can withdraw (cancel) your fair hearing request so you do not have to go to the hearing. You can mail or fax your withdrawal to the Division of Hearings, see How do you ask for a fair hearing? If DTA approved your case or agreed to some or all of what you were asking for, it is a good idea to say so in the withdrawal.
If you can supply the proof within 30 days of the notice denying or cutting your benefits, your benefits should be approved or reinstated. You may also be able to get your worker to approve your case if you supply the proof after 30 days. 106 C.M.R. §§ 702.240, 343.350(B).