What does “Bing saw it” mean in the table?

It is the date on which Bing became aware of your URL through us. Indexing itself is checked on day 7.

Two columns, two different things:

• Saw it: the engine knows the address. It is a date, not a promise.
• Indexed: the address is in the engine's index on day 7. That is what decides the refund.

An address that is known and still left out of the index happens. In that case the credit comes back.