Hi Revista Repeando,
Thanks for reaching out! Please note that when you sign up for a Pro Twitter Stats account we start recording your Pro Twitter data. Twitter Counter cannot display statistics for data that was not recorded. However, we try to get as much Pro Stats for your account from Twitter. Unfortunately, Twitter also has to deal with system availability. Which means in some cases that we can't retrieve historical Pro Stats at all (but most of the times at least a couple of days).
Thanks again for getting in touch with us. If you require further information you can email us at support (at) twittercounter (dot) com.