Q: Not receiving iCloud verification code SMS on my phone nor mac

I have a MBP 17in unibody, an iphone 6 and 4GS. Prior to iOS8, all were synced to iCloud. However, since this year, I am not able to get a verification code SMS on my phone to log on. I used to get he code earlier in January, but the codes would come at least a day after the SMS as been sent. When entering the code, it is rejected as wrong. Now, I do not get any SMS at all. How do I get around this. I have checked all my credentials and the number that the SMS is being sent to is correct and my email address and passwords are correct. I tried contacting Apple support, but not getting any assistance. Let me note that i am in Jamaica. And yes, we are listed as countries where the SMS are being sent from Apple. I look forward to any assistance.