I set my roaming option on before I went to Spain then after speaking to customer service went through the reset of APN settings various times. It didn't work the 1st or 10th time. This impacted on my work as it made it really difficult to check emails. I could only use wifi hotspots and there weren't many where we were staying.
I am curious to know that this issue only happened with ID. I have been going to the same place in Spain for years and never had a problem with other providers.