Your refund status; To contact the IRS, call: Customer service — 800-829-1040; Lost IRS check — 800-829-1954; Refund status — 800-829-4477; Forms and publications — 800-829-3676; Questions about refunds and offsets to IRS liabilities — 800-829-1954; Taxpayer advocate service — 877-777-4778; To pay tax by credit card — Call any of these numbers: