Michelle can only demand her cheque back and no any contractual remedy she can pursue against David.

Explanation:

Certainly, David made an offer to Michelle selling the veterinary machinery. He had expressed his terms of sell contract. Michelle accepted the offer and expressed her own terms to purchase on installments, but her reply never got to David. Later David wrote to her changing his offer. Legally, this means no contract was formed between the parties.Actually, just like the case, Carlill v. Carbolic Smoke Ball Co, there must be an element of not detached offer, for a contracted to be considered legal. Therefore, Michelle can only demand her money back incase David chased out the cheque.

Reference

(2019). Retrieved 25 September 2019, from https://www.deakin.edu.au/__data/assets/pdf_file/0003/728211/carlillvcarbol.pdf