Unable to set mobile data using Celcom NumberShare in Apple Watch SE

Hi, I''ve just received my newly bought apple watch se and paired it with my iphone se. During mobile setup, with many tries I've manage to register with my carrier (celcom) for number shares / multi sim. I've confirm the pairing with my apple watch for mobile data is successful because when I try again to set up mobile data it says "number share can only be pair to 1 watch at the time". However in my iphone watch apps, the mobile data is still not been set yet and my apple watch is not getting any data. In the iphone apple watch mobile data there is no carrier name been registered there and in my apple watch, when I press the cellular button it shows "no data plan" even though when doing the mobile data setup again, it says "number share can only be pair to 1 watch at the time". Please advise.