Not sure a mathematical key can be patented. This is more likely a DMCA violation or simply a failure to license the technology properly (especially given the licensor also controls the store in question).

There are technical/legal ways to get around all this, sure. The issue is that Apple are being uncommunicative and unclear about the violation or are applying a rule violation to something unrelated to the rule. Nothing new with Apple, for sure, and frustrating for RA, but drawing attention to it and being transparent is all you can really do at this point.