The mark of the beast is not yet with us, so don't be concerned until it is with us, then when the matter is clear, all loyal to Our Lord will have to refuse it.
How will we survive without being able to buy and sell? I'm not sure, but that will be our test. For those too weak and give in when that time comes, there is no sin too great for God's mercy. Find a priest, confess it, denounce the mark that you received, and never use it again to buy or sell.