I have many calls to this phone number but it's nobody I know. I was in the US for a few days and I have a huge bill to this number although I have never dialed. Does anybody know anything about this number??

got a blank test message from them the other day

I don't know who keeps testing my phone from this number, but it is annoying.

I got one a few minutes ago, sms message that was "aa"
very strange

lol I got one from this number that said "5" as in just the number 5.  Some [***] hole has some kind of bot texting or is doing this is a prank why we may never know?