Roblox Purchase

I have never used Rixty before. In fact, the only reason I bought Rixty cards was because Roblox gift cards usually don’t come less than $25, and I didn’t want to spend that much. Yes I could have used my debit, but I wanted my kids to be able to do it (give them responsibility, let them type all the work in). NEVER did I think Rixty was something I needed an acct for, and then I could transfer to games. Nonetheless I set an acct up, but now can’t seem to find a way to move it to Roblox! I am seeing conflicted web findings that Roblox no longer supports Rixty. But the Rixty cards clearly says “Roblox”. They wouldn’t false advertise? I imagine that could lead to lawsuits. I just want to find out if there is a way to get it moved over. It’s only $30... but still.. it’s just frustrating. Any help would be great.
Thanks!