Q: lost phone

Blacklist is done by your provider if it's supported.

You cannot blacklist the phone. You can contact your carrier and see if they offer blacklisting. However, there are a number of other things you may need to do regarding a lost phone. See this support document.  https://support.apple.com/en-us/HT201472

Munem 01 wrote:

 

so who stolen my phone he can use after jailbreak my phn??or can delete my icloud account??

I have no idea who stole your phone. You said it was lost, not stolen.

To jailbreak the device they need to be able to remove the iCloud account, and they will not be able to do that unless you provide them the information. They cannot delete it. And if you have a passcode on the device, they will not be able to see your information. And the only phone call they could make would be an emergency call.

Munem 01 wrote:

 

online i see some website offer icloud unlock need to pay 40 euro is it true they offer icloud unlock within 2,3 days mostly UK??

No, it isn't true. iCloud cannot be bypassed.

Correct.