1. on three prior occasions over a two-year period, the olsons were late with the monthly payment -- 25 days, 19 days, and 30 days late, respectively. lender has accepted these payments without comment. recently interest rates have soared and lender wishes it could do something to get the rate of return up on this and other similar loans. borrower is late on the june payment, so on june 3 lender mails borrower a notice saying that borrower must pay the installment by july 3, otherwise lender will accelerate the loan and require payment of the full amount of principal and all interest. the olsons mail a check for the june payment on july 1. lender receives this payment on july 5, rejects it and mails a notice of acceleration. must the olsons pay the entire debt? what arguments and provisions of the documents support each party in this situation?