Philodendron bipinnatifidum birkin pink

I bought this Philodendron at full price but hadn’t noticed that some of the bottom leaves were yellow. A day later one of the leaves was completely rotten. A few days later another big leaf was yellow and mushy. I hadn’t even watered the plant yet cause it was quite moist in its nursery pot. 10 days down the line, it has lost almost all leaves, each one rotting after the other. I repotted to check the roots and saw the mushy stem at its base. Customer service are passing me from one department to another and are being very slow to respond. Very bad service and experience