The fact that the recording was in perfect English was my first clue that the block didn't come from Cuba. A few calls along, Telus personnel admitted that Telus was doing the blocking. And still later, that I could get individual numbers unblocked, one at a time. This they finally did this afternoon, for the four numbers I sent them. They also provided me with yet another explanation, as follows:
"This number blocking by Telus, similar to other telco providers in north America, is because Cuba, among other international countries happens to have several (in thousands) parental ranges of phone numbers that have been identified as being used by hackers, it appears that technology enables them to access thousands of numbers randomly within a certain range. And so once the range is identified they are blocked by the Telco to prevent fraudulent activity.
Unfortunately ligit numbers fall within these rangers, and so Telus has a process to unblock them as they are identified.
I do not know enough about hacking and hackers to know whether this could be true. What I do know that I only got this explanation from Telus after I had rejected several others that were either too vague or completely implausible. How believable it is that hacking is so rampant across Cuba that Canadian phone servers find it necessary to block calls to the entire country seems...well, you tell me! What it seems to me is that if hacking calls are coming from Cuba, then their calls to me would be blocked. But that's not what's happening. It's mine to Cuba that are being blocked!
