This sounds annoying, but it actually happens sometimes with Adobe prepaid licences. Normally the code should extend the existing period, but if it was activated as a new plan, two plans are now running in parallel.

What you can do:
- Log in to your Adobe account (account.adobe.com) and check if the plans are running under the same Adobe ID.
- If two parallel plans are displayed, you must contact Adobe Support directly. Only they can merge the two plans or extend the term correctly.
- Have the prepaid code and your purchase confirmation ready.

You cannot solve the problem yourself, only Adobe customer service can rebook the licences.