Hi! Can you help me with this situation regarding the rights and liabilities of A and B (the topic is contract: consideration and intention to create legal relations)?

A agrees to sell B a product at the price of $1000 paid in $200 installment over 5 months. However, due to some reason, B struggles to pay and asks A for a discount.

A agrees to sell B at the price of $800 but paid in $400 installment over 2 months.

A month later, having just handed B the product, A reverts to the original price of $1000 paid in $200 installment.