The following module enables to upgrade users to VIP group on your website after successful SMS payment. In reply message user receives short text password (key) and following key activation user upgrades his status and moves to VIP group, according to time limit you set.
All data regarding received SMS is stored in a table. Received passwords, sms:keys and plugin settings appear in Admin panel and can be managed there. Rate scale is updated automatically each hour. You can update it manually using module page in Admin panel.