、。。
I don't quite get it, but it seems this isn't going to be straightforward. Hmm.
Literal
Somehow don't-understand [but-が], plain-rope [with-じゃ] go-[unlikely-そうにない] [quot-って] thing [copula-だ] [confirm-な]. Hmmm.
一筋縄ではいかない (literally 'it won't go with a single rope') is the set idiom for 'not straightforward / not easy to deal with,' often of situations or people that resist a simple solution. The ~そうにない frame ('doesn't seem like it will') is the negative of the inferential ~そう — note the difference from ~そうじゃない ('does not look like X'), which denies the seeming rather than the event. ってことだ 'it amounts to / it means that' packages the preceding observation as a summary conclusion.