Bar against direct demand prevents double recovery where tax is deducted at source; risk remains if deductor fails to remit. Bar against direct demand prevents an assessee from being required to pay tax that has been deducted or collected at source under Chapter XVII; it avoids double recovery where tax is deducted (for example by an employer from salary or by a purchaser on transfer of an immovable property). Practical complications arise if the deductor fails to remit the deducted amount to the government, raising questions about recovery from the deductee versus remedies against the deductor.