Correct usage of 'was not having' or 'did not have'?

Solution 1:

Stative verbs like have, be, love are not ordinarily used in progressive constructions, at least in part because one function of the progressive is to ‘recategorize’ an eventive as a stative and statives are of course already stative. When they are used in the progressive, they have somewhat different meanings:

He's being an idiot does not mean He is an idiot but He's behaving like an idiot.

I'm loving it! does not mean I love it but I am enjoying it greatly.

I'm not having it does not mean I don't have it but I refuse to accept it.

In your sentence have is used in its ordinary sense possess, so it should not be cast in the progressive.

Solution 2:

Neither usage is technically incorrect, but they carry slightly different meanings. Almost always, "did not have" is what you intend. A native English speaker would almost never use "was not having", and certainly not in that context.