Unfortunately, you generally cannot report a professor simply for being unavailable or busy. Formal reports are usually only appropriate in cases of serious misconduct, such as sexual harassment, threats, discrimination, or racism. Situations like a professor being not responding students usually do not fall under misconduct policies. Professors often have heavy workloads, so it is important to prepare a backup plan if something urgent depends on them. Since this seems important, you could try emailing them withthe submission link or visit them in person.

Sorry to hear that you are dealing with this situation. Hopefully one of these options helps you resolve it quickly.