would it be Msicheza if the question was to "do not play"
Keep in mind that m- means that it is plural you, not singular you. It's not clear from the English.
Shouldn't rather the last letter change from a > e in a neg. imp. Don't play = usicheze (sg) msicheze (pl) ?
Would be msicheze
What would it be for one person? Usienda kucheza?
From the english version coild be singular..
Usiende kucheze or plural msiende kucheza