Appeared several times on my cell phone bill.

This number has been showing as incoming calls on my bill, therefore blowing up my cell phone bill, but on my actual cell phone they come up as missed calls from random numbers.

It is a Spam and or Telemarketing App called YouMail. You can delete it from your cell phone. It does call forwarding, blocks telemarketers and auto blocks spam callers. You can also set up various voicemail settings to fit your contacts. Someone who called you has this perhaps or you may have it on your phone. Check your apps and remove it if you don't want to be bothered by it.

The calls will show up on your phone bill as calls forwarded to this number. On the settings of YOUMAIL there are auto forwarding. Someone could have inadvertently put your number in and not theirs, thus the wrong number, however it will show the call forwarded number and NOT the number of the mobile phone.

It's all in the privacy policy of their app. Do some research on these issues when they arise instead of complaining on these sites that are nothing more than sounding boards. Your answers lie within, grasshopper!

This number calls all hours of the day even at 4 in the morning and I don't know how to get it stopped

Just discovered that my voicemail had been forwarded to this phone number for an unknown amount of time.