Payment of purchase price at tax sale.

The payment of the purchase price shall be on the terms established by the Mayor. A purchaser shall pay the full amount of his bid, including surplus and costs, within 5 business days after the last day of the sale. If the payment is not received within the time prescribed, 20% of the deposit of the defaulting purchaser shall be forfeited to the District, and the real property shall be deemed to have been bid off to and purchased by the Mayor in the name of the District.