The easiest place to check if you have an active TIDAL subscription, is to go to TIDAL.com or from the home page you can click on MENU - MANAGE ACCOUNT and then sign in.
Then click on subscription. If you have an active subscription you will see a screen similar to the one shown below, with a billing date mentioned above your selected subscription.
If you do not have an active subscription then you will see a screen similar to the image below.
If you do not have an active subscription, please click on the desire subscription you wish to proceed with. Then you will be asked to enter your payment details. Once completed you should see a green check mark on the subscription plan you chose.
Then you are able to log in and begin listening with TIDAL.