Con artists and fraudsters like to prey on the most vulnerable among us, and that very often means they go after older Americans, trying to swindle money out of them. Indeed, it has been estimated that older Americans lose more than $36 billion annually due to scams.

There are so many different cons and scams that it can be hard to keep up, but keep up we should. Here's a scam regarding Medicare that we, our parents, and other older loved ones need to watch out for.

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The card switch scam

The Better Business Bureau recently highlighted a scam involving Medicare cards. The way it works is that a scammer will call an older American, posing as someone working for Medicare. If you get such a call, the scammer will explain that new Medicare cards are being mailed out and that there is a problem with your card. There actually are new Medicare cards rolling out by early next year, so if you've heard of that, you may more easily fall for this scam. The cards will no longer feature Social Security numbers (SSNs) on them and will instead use Medicare Beneficiary Identifier (MBI) numbers in order to cut down on identity theft and other abuses tied to SSNs.

The scammer will explain that either your new card was lost or that someone has tried to use your MBI number. The caller will explain that in order to set things straight, you need to confirm your Social Security number. Once you do, the scammer will have your number and can proceed to try to wreak financial havoc with it.

In another version of the scam, you may be informed that you have to cough up some money in order to be mailed your new Medicare card. You may be asked for your credit card number to rectify the situation. You may also be asked to mail in your old Medicare card -- which has your Social Security number on it.

What to do

What should you do if you receive such a call about a problem with your forthcoming new Medicare card? Well, now that you're aware of the scam variants above, you might just hang up. That's the simplest response.

You should also use the scam to remind yourself how important it is to not give out your Social Security number, credit card number, or any other private information to anyone who asks, unless you're sure of who they are and why they need it. Many scammers can be quite convincing when they call and talk to you -- or they can fool you with an email that really looks like it came from the IRS, your bank, or some other legitimate place. Don't respond. You can, if you want, contact the organization on your own; look up its number yourself and don't use a phone number you were given when approached.