I didnt recive my ZP (Pay by phone)

I don't know why it says 0.00 but it also says at the top 'Please be advised that due to the volume of transactions in process, your payment through this provider might be delayed from 10 minutes to 20 hours.'

You could try contacting the provider directly for help.
http://www.paymo.com/support/
or if it was Zong: For help, please email support.uk@zong.com or call 0843 2189 420.

Strange that for the Zong option you can buy 0 ZP for £10.00 GBP?