percona-online-schema-change is taking a lot of time
You are taking a hash of a phone number?  Why?  Indexing the phone number is arguably better than building a hash and indexing that.  For one thing, the phone number is always(?) shorter than the hash.

Kill the ALTER and rethink the task.

The likely reason for the problem is the randomness of the column being indexed -- Toward the end of the process, it will be slowing down to about 1 disk hit per row.  If you estimate 1ms per disk hit, I would estimate that it might take a week to finish.

What version are you running?  Can it add an index with ALTER=INPLACE?  That might let you (1) add the columns, then (2) in a separate ALTER do the ADD INDEX with ALTER=INPLACE, and not have to worry about it taking a week.

Still I question the need for the columns or the index.

If you need to discuss further, please provide SHOW CREATE TABLE.