Dashes usage for additional explanation after or before a comma?

So, here is the sentence I'm trying to write:

They got to know our business through many different venues - through actually just people they knew, through consulting companies - but I think the most important aspect...

Now, should I put the comma right after "venues" or after the dashes? They got to know our business through many different venues, - through actually just people they knew, through consulting companies - but I think the most important aspect...
OR
They got to know our business through many different venues - through actually just people they knew, through consulting companies -, but I think the most important aspect...

Or I don't need it at all?

Solution 1:

Punctuation doesn't have rules per se but guidelines to improve the reader's flow and comprehension.

Your use of two em-dashes seems perfectly fine without a comma.

However, there are extraneous words which slow your readers down and your through ... through construction distorts the comprehension. It's fine for a speech where the speaker would know where to pause. How about

They get to know our business through different venues—primarily through people they know and consulting companies—but the most important aspect …

Or, don't try to fit it all into one sentence.

They get to know our business through multiple venues: it's the people they know and the consulting companies. But the most important aspect …

Note elimination of phrases like I think in an opinion piece; we know it's your opinion. Also, pick a tense and go with it.

Solution 2:

Typically, the "dash" you're looking for is represented by two dashes, or more properly by the actual em dash character, where that is available. Since the dash indicates a break in the thought of the sentence, a comma (which does something similar, but not as strongly) isn't necessary. When the break occurs between two clauses, there's no need to add a comma in addition.