Apple One

So I recently substituted a free trial for Apple One for a month. It was the individual plan and I thought it was cool. I have family sharing with my mom and sister with our iClouds so we can see what we have purchased and subscribed to. My sister and I’s free trial for Apple Music was about to end so I subscribed to Apple One to extend it but for some odd reason, once I subscribed, my sister could no longer subscribe from her phone. I went to look and see if she had it since we had family sharing even though it wasn’t the family plan and she didn’t have it. Every time I try to find ways to even access the Apple One option, it says she has to pay for it even though she didn’t even get the chance to try out the subscription! What do I do???