Refund of TDS amount received in cash ladger

A supplier to a government office has an unused balance in their TDS cash ledger after meeting their tax liability with available ITC. They are inquiring whether this excess balance can be refunded or if it's considered non-refundable. The advice given is that a refund can be claimed by submitting an application within two years, or the balance can be adjusted against future tax liabilities. The user also raised a concern about potential unjust enrichment.