The SEPE itself has published a guide to help solve them.

People affected by an ERTE resulting from the coronavirus are entitled to unemployment benefit. In fact, this payment has been made more flexible (no minimum contribution period is required to receive the benefit; the time during which the benefit is received will not be counted for the purposes of using up the maximum periods of receipt established by the regulations).

Despite the above, some workers have still not received the benefit, or have received incorrect amounts. And, aware of this, the SEPE has published a document indicating the possible cause of these errors, and explaining how to solve the problem. See some examples:

If none of the company’s workers have received unemployment benefits, it may be because the wrong Contribution Account Code was entered in the collective application for the benefit (the Excel document that the company had to send to the SEPE), or because the workers entered in the document belong to another CCC (for example, if the company has workplaces in different provinces). The solution to this problem is to correct the Excel file and send it back to the SEPE.
If one of the company’s employees has not been paid but the rest have, it may be that the ID card or the current account number is wrong. In this case, you must correct the Excel document and resubmit it, but only with the data of the employee in question.
If the amount of the benefit is wrong (for example, due to errors in the contribution base or in the percentage of the working day), the worker must inform the company so that it can correct the data.