Cenvat Credit rules affect service tax payment timing and eligibility, limiting credit use and requiring electronic payment. Service tax is payable by the prescribed due date each month or quarter, with deposits on the next working day when the due date is a public holiday. Electronic payment via internet banking is generally mandatory, though written permission may allow alternate modes. Cheque tendering is treated as deposit on the date tendered if honoured. Payments require GAR-7 challan at designated bank branches and are rounded to the nearest rupee. Tax may be paid in cash or by debiting the Cenvat Credit register as available on the last day of the relevant period; Cenvat cannot be used for reverse charge liabilities.