Deductions.

A deduction may be taken from gross charges for amounts represented by accounts found to be worthless and actually charged off for income or franchise tax purposes, provided, that: The tax on the amounts has been previously paid to the District; Any amounts deducted from gross charges at the time of or after the date of write-off which are subsequently collected have been included in the first return filed after the gross charges are collected and taxes have been paid on the collected amounts; and The amounts have not been deducted after the payment of the tax on the amounts for periods which are closed by the statute of limitations. Gross charges subject to the tax imposed pursuant to the wireless telecommunication service tax provisions of this chapter shall not include amounts determined to be fraudulent nor shall it include indemnification between carriers intended to cover the cost of fraudulent communication activity.