We had a similar issue recently when 500 tons of wheat sold at was a good value last summer was not picked up. The buyer had been reminded in good time and so we felt that we were right to advise them that they were in default of the contract. We had a friendly exchange of views and resolved the issue with suitable recompense for the "carry" and that should not be a mere £1 a ton a month in this default situation. Contracts are legally binding however they are agreed, verbal or otherwise. All that is needed is an offer followed by acceptance and a consideration. Look no further than the case against The Carbolic Smoke Ball Company. or if you are really keen purchase a copy of Chitty on Contracts.