This is a legitimate call. I was suspicious when the call came through to my cell phone and I did not recognize the number so I left it go into voicemail. I was left a voicemail with regards to a routine security check on my recent debit card, and I was provided a case number. I was asked to call 888-918-7313 regarding this case. I called my credit union and they confirmed that this was their fraud dept and that I should definitely call back. So glad I did. My card numbers were stolen and the card was being used for purchases in Texas and California. Card was flagged and shut down.
I also received calls from 727-572-8822, and did have a credit card problem. However, credit card problem was dissolved, but still am getting "fuzzy" answer machine messages. Message said he needed more information! I never answered his calls - when he called & I did not return his call.
This is a call you WANT to get as it's your bank or credit union trying to verify your purchases. It's to protect YOU. I made several large recent purchases which my bank thought suspicious because I never do this. The # called and was able to verify who they are and my recent transactions with me. If you don't take the call, there's a chance some of those transactions may be denied or frozen.
...scammers are known to spoof legitimate numbers all the time, which means it's better to be safe than sorry and call the number on the back of your card.