I'm sorry you're going through that. I always advise people to avoid third party flight booking companies. MyTrip in particular is extremely bad and often will not respond to customers requesting refunds. In the event that you actually do get customer service to handle your request, they charge $24 per booking to even provide you with service and then $71 per person to request the refund from the airline. And you still pay that fee even if the airline won't give a refund. Just for future reference for everyone, this is all in their terms and conditions, which we all really need to be reading before we give anyone money. And always check reviews on sites like TrustPilot. I always find that booking directly with the airline is best or a trusted travel agent (not a mass online agency). The prices aren't going to be very different and often it's cheapest right from the airline.
If you purchased travel insurance, talk to them about the situation. Or at this point, since MyTrips won't even respond, take it up with your credit card company.