Complex sentence: Lee wanted to sell the sandwich at a very low but more reasonable price, but Leslie forbade it even after Lee reported that he overheard some of the 7-Eleven supervisors and managers complaining that the price of the product was abnormally high.
Split into simpler sentences: Lee wanted to sell the sandwich at a very low but more reasonable price, but Leslie forbid it. Lee then reported that some of the 7-Eleven supervisors and managers complained that the price of the product was abnormally high.