3:40 PM PT -- A rep for Post tells TMZ ... "Post Consumer Brands was excited to partner with Broadus Foods and we made substantial investments in the business. We were equally disappointed that consumer demand did not meet expectations."

12:50 PM PT -- Following Snoop Dogg and Master P's filing today, Walmart tells TMZ Hip Hop, "Walmart values our relationships with our suppliers, and we have a strong history of supporting entrepreneurs. Many factors affect the sales of any given product, including consumer demand, seasonality, and price to name a few. We will respond as appropriate with the Court once we are served with the complaint."

Snoop Dogg and Master P are accusing Walmart of shelving their Snoop Cereal but not on the main floor … a new lawsuit accuses the grocery giant and Post Foods of intentionally hiding their product!!!

The rap legends' attorney Benjamin Crump officially filed docs which TMZ Hip Hop obtained on Tuesday … which allege Walmart and Post conspired together to bury their Broadus Foods company after agreeing to partner with them.

According to the suit, Post first attempted to buy out Snoop and P, and later pretended to share their vision by agreeing to adopt their cereal as one of their own and distribute the product in big-name retailers such as Walmart.

Broadus Foods argues Post should have stacked the Snoop Cereal next to their other top sellers but Post only agreed to the deal to shut them out of the market altogether.

Snoop Cereal launched in Walmart in July 2023 but the suit claims customers complained they could no longer find it a few months later.

Walmart stores online allegedly showed the Snoop Cereal to be sold out across the board … before store employees discovered the product was being stowed away in back stockrooms far away from potential buyers and uncoded to sell in the first place.

The lack of sales cut into P and Snoop’s contract with Post, which they feel was the intent all along -- and they're suing for damages they say fall under the "deceptive trade practices."

We reached out to P for comment … so far, no word back!!!