What arguments would support Associated’s claim for $20,000?

Associated Builders, Inc., provided labor and materials to
William M. Coggins and Benjamin W. Coggins, doing busi-
ness as Ben & Bill’s Chocolate Emporium, to complete a
structure on Main Street in Bar Harbor, Maine. After a dis-
pute arose regarding compensation, Associated and the
Cogginses executed an agreement stating that there existed
an outstanding balance of $70,000 and setting forth the
following terms of repayment:
It is agreed that, two payments will be made by the
Cogginses to Associated Builders as follows: Twenty
Five Thousand Dollars ($25,000.00) on or before
June 1, 2105, and Twenty Five Thousand Dollars
($25,000.00) on or before June 1, 2016. No interest will
be charged or paid providing payments are made as
agreed. If the payments are not made as agreed, then
interest shall accrue at 10% per annum figured from
the date of default. It is further agreed that Associated
Builders will forfeit the balance of Twenty Thousand
Dollars and No Cents ($20,000.00) providing the
above payments are made as agreed.
The Cogginses made their first payment in accordance
with the agreement. The second payment, however, was
delivered three days late on June 4, 2016. Claiming a breach
of the contract, Associated contended that the remainder of
the original balance of $20,000, plus interest and cost, were
now due.
a. What arguments would support Associated’s claim for
$20,000?
b. What arguments would support the claim by the
Cogginses that they were not liable for $20,000?
c. For what damages, if any, are the Cogginses liable?
Explain