What test do I use for two variables that are ordinal and seem to have a non monotonic relationship?

I'm trying to find the right test for association for two likert scale, ordinal variables from a questionnaire I did:

1."How often do you recycle" - (1) Almost Daily, (2)2-3 times a week, (3)Once a week, (4) Less than once a week, (5)I don't recycle
2."Recycling can conserve the environment" - Ranges from (1)Strongly agree to (5)Strongly disagree, with (3)Neutral in the middle and a (6)I don't know option.

After graphing the data from my two variables together, it seems to that they don't have a monotonic relationship. From what I've searched, Kendall's tau c might suit my situation but I'm not sure if its a good idea since they don't have a monotonic relationship. Can anyone suggest what test to use? Thanks!