an interest of between 0.5 to 10% of the contract sum per day shall be applied to the contract sum. Following the neglect, failure and refusal of the Defendants to pay the Plaintiff, the Plaintiff, by a letter dated 14th April, 2015 gave notice to the Defendants of its intention to apply the interest in accordance with terms of the special condition of the contract. By a letter dated 24th April, 2015 the Defendants admitted owing the Plaintiff the sum of fifty six million, four hundred and fifteen, four hundred and twenty two naira (N 56, 415, 422.00) to be paid in two tranches. The first tranche of the sum of N35, 717, 422 (Thiry five million, seven hundred and sixteen thousand, four hundred and twenty two naira only). The second tranche will be N20, 698, 920.00 (Twenty million, six hundred and ninety eighty thousand, nine hundred and twenty naira. The Defendants have paid the sum indicated in the first tranche but the second tranche of N 20, 698, 920.00 (Twenty million, six hundred and ninety eight thousand nine hundred and twenty naira only), has remained unpaid till date despite repeated demands. The Plaintiff, by a letter dated 23rd September, 2015, indicated its intention to initiate arbitration proceedings against the Defendants in accordance with the provisions of the contract but the Defendants did not respond or indicate intention to pursue that option. 10