I had to cancel some non-refundable tickets due to death of an immediate family member. Delta website said I have to mail in the death certificate and ticket information. I did that. Does anyone have experience on how long will it take for Delta to response on this type of request?

What do they normally do? No refund at all? Waive the change fee (I do have credit for the tickets for the next 12 months)? Give us vouchers? Refund my credit card (Seems unlikely)?