Is there a mistake in buying aliyah for the Torah?

In the SD
Peace and blessings to the rabbi, I hope you are well.
Last Shabbat, it turned out that the Torah reading was not according to the division in the Pentateuch. There were several adders who read new sections, so the original purchasers received a shorter section.
In a conversation with one of the worshippers who purchased it, he did not want the money back but claimed that it was not right (I agree that it is not right, but life is dynamic and sometimes changes on the fly).
My question is whether there is a halachic problem here of buying and selling (it’s a bit strange that I’m asking about buying and selling on Shabbat) or whether this is an accepted norm. The question stems from the variety of synagogues. Some of them add regularly, and therefore this case is not exceptional, and some of them do not, and therefore this case is exceptional for them. For us, as stated above, it is an exceptional case.
Thank you in advance and wishing you good news.