Surrounded by Innumerates

I get home after being away for a couple weeks, and amidst the accumulated mail, there's a bill from a certain large department store chain that rhymes with serial killer John Wayne Gacy asserting that the store card card was used to purchase a few items of clothing, nothing extravagant, $38.12 total, and that oh, I should pay it by... today, or they'll tack on a dollar finance charge. So of course I go right over to the local store and pay it.

While I'm there, I note that at the bottom of the bill, there's a stated annual rate of 72.24%. That seems a little odd - even though I missed one of their bills a year or so ago, the rate really shouldn't be more than somewhere in the twenties. Not that it matters, as I don't carry a balance and hardly even use the card. I mention it to the cashier, who says, laughingly, not to be late.

After doing some math and figuring out that the daily periodic rate stated next to the annual rate multiplies out (1.0006822 to the 365th power) to about 28%, not 72% (which would be 100% minus 28%), I decide to call their customer service department... which is closed.

Their automated voice system tells me that my balance was $39.12 (which it wasn't; it was $38.12 since I paid on time) and that I paid $38.00 (which I didn't; my receipt clearly states I paid $38.12).

Given their apparent inability to do any kind of math at all, count money, et cetera, I've decided that these really aren't people I feel like having a credit account with. If I do buy from them in the future, I'll pay cash, and I'll count my change very carefully.