e-Wolfe, I have thought about the interest part and I think it is an individual decision to make.
This is my take (I am not a lawyer). In principle, I strongly believe that CB is liable to pay interest for the amount due in the Dec 2005 from the date of your Dec 2005 statement to the date you formally submit your claim to BFSO, and that for the Jan 2006 from your Jan 2006 statement to the same claim date. It can be easily argued that it is unfair for CB to be liable for the interest while waiting for the BFSO decision.
I have read that BSFO ruling on interest is usually based on the market deposit rate (approx 5%pa ?).
So, the bigggest factor to consider is how large the amount is. I believe taht most of us did not take too long before we make the claim formally. So, the relevant period is probably 2-3 months.
That way you can work out how much interest you can potentially get back without too much stress. I suggest that arguing (for my case) for a 12 months' interest can be very difficult and possibly stressful ... diminishing returns for this effort.
CB had somewhat reversed all the interest I was charged for the Nov2005-Feb2006 period. I am not sure why but I have the feeling that it is relevant to this dispute. The reversal was made well before the BFSO decision was known to me. Perhaps, CB had already known earlier and anticipated further claim and consequently (wisely) reversed the interest.
The difference between my 2 months interest on outstanding cashback (at 5% pa and the reversed interest is quite small. Thta is why I decided to let it go.
Also, my wife had reminded me that the reason for this fight was to prove a point. And I have won and proven my point. My point ? I was very crossed with the stealth manner CB cancelled my life-time-low-interest-balance transfer privilege I had before this scheme. At the same time, CB tried to force us into a corner with the $160 fee. The cashback scheme was a perfect opportunity to not only regain my losses but also to beat CB big time. When they refused to pay, it became a crusade. Now, it's over (almost). I am still thinking whether I should be a social warrior. What about those who are not aware of their rights to claim against CB ? And those who were intimidated to accept the meagre $500 settlement ?
e-Wolfe (and others), you have your rights but there is a cost too.