Bad lunch experience

Brought a Godiva drink to a 'Bubble tea' cafe for lunch yersterday. After serving us, the waitress told us to remember to clear away the 'outside drink' before we leave. Was wondering, is this the service standard we deserved? We had lunch in their cafe and its only 1 drink we brought in. My dear dear even order another drink for himself in the cafe. why can't they throw it for us?

By the way, the cafe is located in Toa Payoh central.