OP
two clown resort
Registered
In addition to the steps mentioned above (that is, check assembly/ threading of cam strap, wet the strap before putting on tank), you could also consider adding a second cam strap. You will still need to sort out issue with first strap, however, a second strap functions to secure tank very tight (both side to side and up and down).
I emailed them on weekend. Hopefully they will get back to me. I am very curious of the company that manufacture this BCD.