I would like to use a picture on social media channels which is no longer available on Adobe Stock. Am I allowed to use it anyway? Can I use a Copyright reference to Fotolia where I originally have bought the Picture?
You have acquired a license according to the license terms at the date of purchase. It's important that you keep those terms with your picture. As you have acquired via Fotolia, it is OK to reference Fotolia.
If you would have acquired on Adobe stock, the license is perpetual. So you could use it.
ABAMBO | Hard- and Software Engineer | Photographer