I’m subscribed to the FREE Membership.

I’m subscribed to the FREE Membership. For each message sent 6 credits are debited from my account. Why 6 credits if the price of processing and translation of each message is 3 credits?

The 6 credits are debited from your account for the translation and processing of your message (3 credits) and for translating the response you will receive (3 credits). In this way at the entrance of every message your balance remains intact and you pay 6 credits for 2 messages.