Non-PRO Japanese to English Art/Literary

I'm having some trouble getting the exact meaning of the sentence below.

First of all, how should "二転三転" be translated?

I'm having the most trouble with this portion:

学説を「二転三転」させてきた研究チームの主張だから

How should "主張" be translated here?

すると工場および少なからぬジャーナリズムは，学説を「二転三転」させてきた研究チームの主張だから，○○○○説は「信用できない」「またすぐに別の説に変わるのではないか」と述べて，研究チームおよび○○○○説の「信頼性」を低下させるキャンペーンを行なった。

Here is my attempt:

Thereupon a campaign was carried out to lessen the “credibility” of the research team and the ------ theory, through which the factory and a considerable amount of journalism stated that because of the research team’s persistence, which had caused a “backtracking” in theory, the ------ theory “could not be believed” and “It will probably soon change into another theory.”