Hi there! As of June 17, 2019 ESO Plus members on Xbox One will receive all Crowns for their membership period when it starts. For example, if you have a three month membership, you will receive 4,950 crowns when it renews.
If you had a three, six, or twelve month membership prior to June 17th, you should have received the balance of crowns due to you the next time you logged in. If, for example, you had two months left on a six month membership, you would have received 3,300 crowns when you logged in.
In general, if you have waited longer than 72 hours since purchasing ESO Plus on console, and have not received the crowns included with the membership, you may contact customer support here: https://help.elderscrollsonline.com/app