I run a small catering business and recently secured a contract to supply meals to a local company for 6 months. We agreed verbally on pricing and delivery terms, and I started supplying. Now, two months in, they are delaying payments and saying they want to “review” the pricing due to internal budget changes. I don’t have a signed written contract, only WhatsApp messages confirming the agreement. I’m worried about cash flow and whether they can legally change terms like this after we already started. What rights do I have in this situation, and how can I protect myself moving forward?