Which debt is better to target first?

See, you need to pay off your mortgage debt on time. I believe you have provided a collateral while taking out a mortgage loan. So, you might put your collateral at risk by missing the payments. And talking about credit cards, they are usually unsecured loans. You don't need to keep any collateral but the interest rate is incessantly high!
I would suggest you to consult a genuine debt relief company. They can guide you to opt for debt relief options based on your loan amount and financial condition.

Consider debt settlement for your credit card debts. And talk to your mortgage loan company to consider the missed payments. Try to stay current on the mortgage.

Ofcourse you must pay off the mortgage debts on time. Remember you might lose your home if you do not pay the monthly installments. On the other hand you might be able to negotiate with your credit card company to reduce your debts, it's possible.