Iberia Airlines charged me twice then canceled the ticket with no refund??

I am so close to a breakdown and made this account in hopes of suggestions for how to handle this situation.

6 months ago, I booked an $850 flight ticket for my father with Iberia Airlines. They charged my card twice for the flight, so I've been calling and submitting their online form since then. Every time, I get told that I will hear back within 24-48 hours or 7 business days, then CRICKETS. I have spent well over 40 hours of my life on the phone with Iberia.

Today, my father shows up to the airport to board his flight, and we haven't received a refund or response yet. They sent him an online check-in email yesterday. When he tries to check in at the counter, they tell him his ticket got canceled (???) and provide NO explanation for why, just that '"it says 'canceled' in our system". He pays $1600 for a new ticket on the spot, as he needs to attend my sister's graduation ceremony tomorrow.

So now, I have paid $3300 in total for this $850 flight, and every time I call Iberia's customer service number, I have to deal with a new person who demands all the details again, only to say "you will hear back within 7 business days". They refuse to transfer me to management or do anything concrete. I have called Iberia 4 times today to resolve this, and all I have been getting is "you will hear back within 7 days" (as I have for the past 6 months!).

I am at my wits' end over how to get this $2500 back from Iberia. It has been 6 months of begging to no avail. Is there anything I can do beside call the same number for the 40th time? Like any protection I have as customer? Legal action? The ticket is for Casablanca <-> Boston if that helps. I am located in Canada but the passenger is based in Morocco.

Unfortunately, I have tried to take this up with my Moroccan bank to no avail: they're saying they need Iberia's response before refunding me.