Bought plainswalker card from in game store, and it didn't show up in my collection.
Playing on PC. I bought a chandra plainswalker card from the daily deals section of the store, it shows as purchased but does not show up in my collection.
You didn't buy the card, you bought the fullart varient look. Once you get the card you can change from its normal look to varient.
For this issue, please submit at: https://mtgarena-support.wizards.com/hc/en-us/requests/new and select 'General Questions'.