URGENT: Freezer is defrosting!

I have a Frigidaire freezer/refrigerator. Recently, the freezer and refrigerator have been warming up, and the food inside is defrosting. If this issue isn’t solved quickly, hundreds of dollars in food will go bad! The freezer is blowing slightly cool air, but it is not cold enough to prevent the food from defrosting. In fact, it has already defrosted. The refrigerator soon began getting warm after the freezer was and the food in there is cooling down, as well. Before this issue began occurring, I kept hearing this “bonk“ sound from inside the freezer. It was subtle at first, but eventually got louder, to the point where there is a “BANG“ instead of a “bonk“. This only occurred when the freezer stopped running the cooling unit. The sound would repeat several times before stopping. Is there anything you can suggest? Thank you! This needs immediate attention.

P.S. Honestly, I’m panicking a bit because a lot of food will go to waste if a solution isn’t found fast. Please give me any suggestions you can. Thanks!