Hello, I am Yoshi from NILS Japanese language school.
[もう Vました]
もう means “already” and is used with Vました. In this case, Vました means that the action has been finished.
The answer to the question もう Vましたか is はい、もうVました or いいえ、まだです.
(Example)
もう　荷物（にもつ）を　送（おく）りましたか。　　　Have you sent the parcel yet?
—はい、[もう]送りました。　　　—Yes, I have [already sent it].
—いいえ、まだです。　　　—No, not yet.
*荷物：　parcel, baggage
*送ります：　send

In giving a negative answer to this type of questions, you should not use Vませんでした, as this simply means you did not do the specified task rather than you have not done it yet.

July 10th News, from NILS Japanese language school.