Help me please! – LearnEnglish Grammar (US ed.) Review

This is really good app to improve your English skills. I bought all packs, but when I try to open for ex. "Elementary pack - Imperatives (+/-)" it is inactive to be opened, it said "Elementary Pack 1 has already been purchased." fix this problem I'll appreciate that!
Review by alextropics on LearnEnglish Grammar (US ed.).