Ultramel custard sad experience

Hi all, I recently purchased ultramel vanilla custard about a month back.

On the 4th-5th of March 2018 - a small portion of the custard was consumed and balance was kept in the refrigerator. This pass weekend upon attempting to consume the custard - the custard didn't smell or taste right. The expiry date on the product is 28/03/2018. Upon contacting ultramel danone customer services - I was informed my complaint will be escalated. Unfortunately no mention about compensation from the lady from customer services. Rather I was informed that the print on the box says consume product within 3 or 4 days of opening. Very sad outcome from ultramel