Paypal is available in Montenegro and you have a Paypal personal account open.
Also the option to receive paypal payments is sadly not available in Montenegro. HOWEVER you can send payments for purchases but it has to be funded by your (confirmed) visa credit card.
Paypal varies a lot country to country and can only offer the services that the banks / governments of that country allow it to offer. There are quite a few countries unable to receive paypal payments.