You won’t like having to go back on your word, but you have no choice when Mercury retrogrades past the Sun on December 22d. It’s clear that you over promised and now must renege; however being a Capricorn means you won’t leave people in the lurch. Either you will reschedule for a later date or devise a plan to deliver in installments. Meanwhile try not to be too hard on yourself. Everyone makes mistakes and yours is hardly the worst. Knowing that you’re committed to making good will satisfy the disappointment and knowing you’ve learned your lesson so that this never happens again will reassure you.