change discontinued email apple ID on iPad to new apple ID used for iPhone

There are two possible ways you got to your current state:

1. You changed the old Apple ID to a new one. In that case, your Apple ID should have been properly charged and the article above should assist further if required.
2. You created a new Apple ID, having nothing to do with the old one. In this case (likely), you look like a completely different person and no longer can use anything associated with that old Apple ID.

If you have sufficient iPad proof of purchase documentation, see “Start a support request” here.

How to remove Activation Lock - Apple Support