The miles should post within 48 hours.

Don't forget to check the availability before buying the miles:

Outbound at 9h12am, 11h09am, 12h42pm, 13h46pm are available on sunday;

Latest return flight available is the 7h15pm on sunday; on monday the 6am, 8h09am and 10h15pm flights only.

If you call they should allow you to hold the ticket for 48-72 hours while the miles post.