Did you do what the message said - "contact customer support"? That's what you should do. WARNING: now you have posted, many scammers will contact you, pretending to be from Adobe. They will offer to connect to your computer to fix this, to sell a solution, or ask fot your credit card or Adobe login password. You need to be very careful, and sharing a serial number with the world is really not a good start (doing this can lead to losing the use of expensive software, or worse).
Adobe WILL NOT contact you. You have to contact THEM.