I have had several similar comments from a USA buyer that always say the same message:
“020920…pd’v…thank’s…”
What does this message mean?
Is it automated message or something?
hello, I think it’s nothing bad, the numbers indicate the date they made the purchase or downloaded the application.
020920: date of purchase
pd’v: I don’t know what it means
thank’s: Thank you
You are lucky you can read it 
I get a lot of comments where people just type miscellaneous characters, but they leave a good rating, so I don’t worry. I just reply thanking them for their purchase! I would not worry about this message, they will email you if there’s an issue