If I mail my visa applications, which payment method can i use? and how and where?

You need to pay through remittance. When your passport is ready for returning, the staff from CVASC will inform you the amount of money you need to pay.
Here is the information about the account:
Beneficiary’s Name：CITS V Service (Spain) S.L.
Bank Name: La CAIXA
Account No: 2100 2123 16 02 00324738
IBAN: ES38 2100 2123 1602 0032 4738