TD Canada Trust Bank stole from me - what would you do?

TD Canada Trust stole from me, and I'd like to cloudsource (sorry) some advice. For over a decade I've had a TD Visa card with TD Canada Trust, one of the major Canadian banks. Some months ago I was looking at my statement and saw they had charged me $45 for "Balance protection insurance" I'd never requested. I looked back through older statements and found they'd been charging me for over a year. Monthly amounts ranged from $30 to $120 or so. I called them up and they said I must've requested or authorised it, because it's an opt-in programme, so they'd pull their recording of the phone call in which I'd said "yes" and play it for me to remind me. That would take 4-8 weeks, so call back then.

I called at the 5-week mark: No, they hadn't retrieved the call yet, because it was such a long time ago. I must've said "yes" and just forgotten, because it's an opt-in programme and they're not allowed to add people to it without an explicit "yes", but as a courtesy they'll dig up the call and play it for me. Call back in a month.

I called yesterday: No, they hadn't retrieved the call yet, and weren't sure how long it would take because mine wasn't the only call in the queue waiting for retrieval (Oh, does that mean I'm not the only customer involuntarily opted in...?) but I should call again tomorrow (i.e., today) and speak with one of the two people who handles this kind of call.

I called today: Er...yes, they were able to retrieve the call. Er...yes, turns out I was right all along, I'd actually said "no". Er...they're very embarrassed and sorry. Er...this isn't how they normally do business. Er...they'll be issuing a full refund for premiums paid (just shy of $1K).

"With interest", I said.

"Er...well, that would...um...we don't usually...I mean...we don't know how much that would be...we'll have to look up the interest rate on the card."

Where we left it this morning is that they'll process the full premium refund immediately and I'll see it applied to my card within 5 days. Within 3 days, the responsible will call me back to discuss interest. Repeated apologies, "we're going to coach our people", etc.

Their utterances today -- all of them -- sound an awful lot like "Ohshît, we effed up and you caught us". Yes, they did. And yes, I did. I don't think they really expected me not to mention interest, and I think they might be hoping a magnanimous show of "agreeing" to pay interest will make me go away without pursuing this beyond "Hey! Give me back my money, you creeps!".

But the more I think about it, these people stole a thousand bucks from me. The fact it took me awhile to notice is immaterial; if I hadn't noticed, they'd've kept right on stealing from me in perpetuity. Also immaterial is their promise to give the money back in a week, three months after I noticed they were stealing it from me. It's still theft, just like if I absentmindedly walk out of a store holding a piece of merchandise I'd picked up off a shelf, it's still shoplifting even if I meant to pay—or even if I unilaterally decided a store employee had told me I could have it.

It occurs to me the interest rate on the card is somewhat less than relevant. That's the rate they set for when I borrow money from them, but what happened here is that they "borrowed" (stole) money from me. Which suggests that I should be the one determining the interest rate, and as far as I am concerned they're a bad risk.

Moreover, I'm not entirely sure money-back-with-interest is sufficient recompense. They outright stole my money and had the nerve to tell me I had told them to help themselves to it. What's to stop them doing it again? It's a pretty good gamble most people won't notice or have the time or energy to pursue restitution.

Please keep in mind this is Canada, not the United States. I don't think hiring a lawyer would be cost-effective because this is $1K we're talking about, not $10K. And I haven't looked at the credit card user agreement to see exactly how stacked against me it might be. So, here's where the advice part comes in: What would you do?