ITC REVERSE in GST

A client claimed Input Tax Credit (ITC) in 2017-18, but their supplier has yet to upload the relevant invoices. The client now wishes to reverse this ITC in the current year. The key question is whether this reversal is permissible, especially since the client has already paid the invoice amount, including GST, to the supplier. This raises concerns about whether the supplier has remitted the GST to the government or filed their returns.