Amazon does not ban people without telling them. If your account is banned then you would have gotten an email to the primary contact saying that is the case.
There is a link checker in the associates area that allows you to input your link to test if it is working and linked to an active associates ID. Check your links with that.
When you say you had 5,955 clicks last month and 2,029 clicks this month is that what Amazon is reporting or is that what your analytics is reporting? Are these all from countries on which you have an active Amazon associates account? If you have 8000 clicks to Amazon from US traffic with no sales then there is something wrong... my experience is that 100% random/untargeted US traffic to Amazon converts at like 1% just because people order from Amazon frequently enough that they will place some order in your 24 hour window at around that rate.