This happened to me once, and it ended up taking about 6 weeks before they back got to me. It was a similar “just wait” response the whole time until then.
It turned out to be a very simple change they wanted, but because of the nature of the change I think it’s something they needed to consult their legal team for.
So if they are not giving you any info, but you are able to make an educated guess about what change they might want, you can reject the binary and re-submit. Otherwise you probably will just have to wait.