BBB is not a boyz club from my experiences. Once I've had to escalate to BBB with major dealers, they have provided at least a reasonable resolution before BBB closes the case. Last time I did it was with a new car dealer who wouldn't give me a $500 deposit back on a lemon that didn't work out. They wouldn't reply to my calls until BBB got involved. And that record stays there forever. Nothing to lose imo.
The first time this siding came loose, I'd have gotten involved finding the root cause. And after the 2nd time only a week later, I'd have demanded a reason why it came loose and something in writing that would guarantee the "fix" for years. 5 attempts after 5 years? That's just insane.