Michael's hunch seems correct here. I will send you a private message soon with more info that should help you sign into the correct (ssubscribed) account. Important: do NOT uninstall the app. Deleting Lightroom before it has synced images to cloud storage will cause data/image loss. Just as a safety net, let me recommend you do a full iTunes or iCloud backup of your deevice before trying any next steps, so you can always recover images in the Lightroom app cache later.
To get all your images from your separate, free account copied over to your paid account, you have some options:
1. My top recommendation, which will preserve your original images and also your edits. In your paid account, create a shared album, and then invite your free account to join it. Be sure your paid owner of the shared album has applied "Can Contribute" settings for the free user in the shared album settings. After your free account accepts the email invitation, sign into the free account again in Lightroom, and then add all the photos it has to the shared album it just joined. Let this sync to your paid account, and then sign back into your paid account. You should not see all your same photos in the paid account. See this help page for basic info on how to set that up: https://helpx.adobe.com/lightroom-cc/using/save-share-photos.html
If all that is too complicated, another option is:
In Lightroom, sign into your unpaid account, select all images, and export them to your camera roll. You will need to decide to export originals, or copies with your edits applied. Then sign into your paid account and import all your images from the camera roll. I do not recommend this if you're dealing with many images, or losing either your edits or your original images is unacceptable.