Complicated?

It was my birthday last month and my sister bought me a Netflix card. Now that we can no longer use it, she claimed that it was my turn to pay (we share an account) which I find totally stupid because she had given me the card and it was actually mine. I would like to prove to my sister with an answer that I'm right😂 Oh yes, I wouldn't have an account before my birthday.

Aha. And what is your question

Yes, I wanted someone to write who is right here😂

I don't know, I would just flip a coin and then take turns paying. Can be interpreted in different ways.