Broken prongs where memory card seats.

Not sure you tried all the things I should do.
Be sure the cards are formatted, and try to format them in the camera.
But before you put in any card, check with a bright light close to the memory card slot, if all the contacts are clean and free, Just a little bit of dust or paper on one contact, could spoil all the fun. The contacts should be clem and shiny. All straight and to one side, Not one can be a little bent. If someone ever pressed a memory card in the camera the wrong way around, a lot of damage should be seen down there with some contacts bent or broken.
And be sure you did not switch all the cards to the lock position.

You need to have a look at the slot where the memory card goes in. Using a light, look down in the slot at the pins the match up to the card. There may be one or more bent or broken. If the pins are damaged, then it would be a major repair. Usually once they have bent, trying to straighten them back causes them to break off.

SD cards have a slide switch along one edge. Slide it away from the contacts to protect, toward the contacts to unprotect. If that doesn't do it, try a different memory card. If that doesn't do it, then the detector inside the camera may be broken.

Wow, CF cards. Well, as you said, the prongs broke which means you need it repaired. http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=139&modelid=11154#SupportDetailAct

Advice: If you can, sell that and upgrade to the XTi or XT1 version of the Rebel. Now they use SD cards which doesn't have the prongs to break off. Also SD is more of the major memory card that is compatible with electronics. Otherwise, get a point and shoot. They are cheap and also use SD cards.

Repair cost:
2 Prongs replacement = All the prongs replacements. I'm not sure if they have that type in stock anymore. My guess is ranging from 60-100ish USD. Usually they will check to see what is the problem and bill you for their labor and parts.

It can be very difficult to see if the pins are bent, and harder to see if any have broken off. Do not probe with anything that can bend the pins. I suggest you create a small tool from a strip of paper and a toothpick. Pass the strip of paper over the pins while watching with a strong light. See if you can count each pin this way. A broken or missing pin will require repair by a Canon authorized facility. Your work will save you a diagnostic fee.

THis is simple. Either your memory card has not enough room, the memory card is broken or the slot you are putting it in is broken. Try putting it in the other slot.

If this phone is new, there may be a dummy card that is in the slot for protection. remove the dummy card before you insert a real card. If the phone is not new and you have inserted one before, there may be an obstruction blocking the slot or, the cooper prongs are bent.

The memory card is supposed to slide over top of those pins, they would need bent back down but I can not think of an easy way for you to do that yourself. If you have a service plan, now might be the time to use it.

Hope that helps...

Geno

You may have bent or broken contacts inside the card slot. It's tough to see, but if you look deep inside the slot, you may notice a contact bent or broken. If you're not able to see any damage inside, try taking a cotton swab with some alcohol (isopropyl, not rubbing or drinking type), and cleaning the contacts.

Yes, memory card pin set are available for replacement. Unfortunately, camera needs to be disassembled to some point to replace it. The average cost may run around $75- $125 in US repair shops.