Simply replace the unfilled areas such as "" and "[date]" with your information.
Notice is hereby given that we cancel our contract dated [date] for the sale of [description of goods] to [name of firm], for the following reason.
That on [date], you breached said contract in the following respect:
Cancellation of said contract is effected in respect to that certain installment delivered on [date], and for any subsequent delivery of goods, contracted for in said contract, inasmuch as your breach impairs the contract as a whole.
We claim damages from you in the amount of [$]