Thank you for your question.
To get access to FotaWeb platform please contact your sales manager and provide him with the e-mail you will be using for your account. FMB001 is a 2G device and does not use the 3G network, also it is not recommended to use SMS data for records sending. Data usage will highly depend on your configuration. It would be difficult to say an exact number, minimum AVL packet size is 45 bytes (all I/O elements disabled), maximum size for a single AVL packet is 783 bytes, send period, (On moving/On stop) and any additional configuration will impact the usage.
Hope this helps,