This solution doesn't work properly with double input data.
for examlple try volume = 0.027, side = 0.3
You have to consider accuracy range.

JS: Node v12 should be used along with its appropiate assertion tools (Mocha + Chai).
Refer to this and this

About the negative numbers, also in the description:

sumMul(4, -7) ==> "INVALID"

About m is included, see there was already an issue below. Closing.

C# Random test is not correct.
there are negative values of n and m (in description: positive integers).
m is included to the multiples (in description: m is excluded from the multiples).