1. make sure the country got offer free data backpack

2. make sure you connect to the correct Telco provider

so far there is no accident for user who always travel to singapore or nearby countries
try to restart ur device

for your case, few possibilities

1. you are still with ur previous telco, not done with the mnp, existing sims card got problem ( check if sim registration fail / no response when insert old card )

2. stuck with the processing status which both not active now ( may provide me number to check if active @ umobile side )

3. they successfully port into WRONG card provided (solution same as 2nd , i may check if the Sim serial correct )

normall around 1 working day for most telcos if REPLY the confirmation SMS correctly