My minecoins disappeared

I had recently bought 960 minecoins to purchase Pets 2 in the minecraft marketplace on my phone and i had 90 left over minecoins after buying the world. (I had 60 minecoins before buying more. Then after purchasing the 960 with the bonus 60, I had a total of 1,080. After buying Pets 2 for 990 minecoins, I had 90 remaining.) I had logged out of my xbox account to let my cousin play the game. Once I log back in, my minecoins were gone. Everything I’ve ever bought was still there, except for my previous remaining minecoins. I do not know what happened, but it would be nice if I could have those 90 minecoins refunded. Thank you for your time.