Please help me identify whether this is a liar.

This is not a liar, it is really a mistake. At that time, the other party may not have noticed, but it is impossible to cancel the recharge after discovery. Because it is impossible to cancel the recharge in the air after two minutes, first of all, will you check whether your phone bill is 30 yuan more? If so, help him mend it. Thirty dollars is no big deal

Why did he call with another number at that time? Because his own number is out of money. Later, in order to convince you that it was really wrong, he filled his own number and called you.

Not a liar.