I purchased a $15-00 SIM card in Singapore on the 10th Apr and was told that it would work in the countries that I would be visiting. I have not been able to use the SIM since leaving Singapore. Today we are in Vietnam and I am told that I cannot use the roaming as my balance is less than $3. According to the plan that I purchased I would have 1GB untill the SIM expires which is 6 months from the 10th Apr. Please adivse as I feel that I have been misled if this is indeed the case.