I haven't had that problem but there is a way to get it opened until the dealer can fix it. First, what are you driving? You have not given us any info at all. What model, year, etc.
IF it is a Santa Fe Sport, or at least a SF, there is an emergency release inside the back in the cargo area. Same side as the filler opening, open the back hatch and look on the left side. There is a door there with a manual release inside. If you have the owners manual look on page 4-38 and you will see a pic of the hatch and release.
My manual is for a 2013 Sport, yours might be different if it is a different year or model. I am assuming it is a "Hyundai".:smile: