I had an accepted paper at a production stage, when I became aware of a technical error, which I was able to fix (in case it matters: the field is mathematics, and even though the claims I made in my paper were correct, they did not have adequate proofs in the earlier version). When I sent the correct version to the journal, they told the production team to halt the publication of my paper, and sent the new manuscript to the editorial team and the original reviewer as the change was deemed significant.
A few months in, while presumably the new edition was under review, the production team published my old manuscript with the gap anyway even though they were not supposed to. When I let the production team of this incident, they maintained that only thing they could do now was to publish an addendum.
While this response seems reasonable (while it's regrettable that they made this mistake), the details of their response seem odd.
First of all, on the addendum, they said:
What we can do is issue an addendum notice (NOT an error notice such as an erratum and corrigendum) and note any additional information that was present in that revision to the addendum. I.e., “Post-publication, _____ was brought to our attention. In this addendum, we lay out additional research/information/etc….” and then proceed to include any of the additional revision work that was intended to be included in the original article.
The language the production team suggested is not precise (as the gap was spotted before the publication) and puts me under a slightly worse light, unless by "i.e." they meant "e.g.," in which case I can say what I see fit.
Also, the production team erroneously believe that I have several papers in production with their journal, which is not true. This shows that I may have confused the production team; I certainly do not want, e.g., to have both versions of my paper published.
Unfortunately, when I asked them for clarification regarding these details, they stopped communicating with me. How should I proceed with the conundrum?