KANSAS CITY, MO (KCTV) - Every time you leave your receipt behind at a restaurant or don’t double check the charge, it could be costing you.

Odds are, you might not catch it.

Bob Bliss contacted KCTV5 News to warn others about his experiences. He says twice, servers have changed the tip amount on his check, adding more gratuity than he initially authorized on the check.

“This is really disgusting to me. It’s disgusting, and if they're doing it to me, you know they're going to do it to a lot of people,” Bliss said.

The first time happened several years ago a sub sandwich restaurant. Bliss said a cashier at the take-out counter added in a $10 tip on a check for a $9 sandwich. That employee was later fired after Bliss contacted the manager.

Most recently, Bliss says it happened at a Chinese buffet in Raymore. He contacted the manager when he realized his credit card statement didn’t match his receipt from the restaurant. The restaurant charged him $3 more than he authorized.

Bliss told the manager he believed someone altered the check after he left, changing his $1 tip to a $4 tip.

The restaurant manager offered to refund the $3 but told Bliss he needed to drive out to Raymore to get it or give his credit card information over the phone.

“I said, 'I'm not giving you my credit card information. You’ve already robbed $3 from me once. I'm not going to let you do that again.' They just basically said, 'Well, I'm sorry and that's it,'” Bliss said.

So KCTV5 went to Raymore to ask about Bliss’ refund.

The manager was not there at the time, but when asked about Bliss’ receipt and refund, the employees there were aware of the situation. No one admitted fault, but an employee gave KCTV5 $3 and showed KCTV5 the following restaurant copy of the receipt.

The $1 tip had in fact been changed to a $4 tip. Numbers were also altered to make the total bill $25.67 instead of the $22.67 total on Bliss’ copy.

The restaurant manager later told KCTV5 over the phone that the restaurant does not admit fault and accused Bliss of changing the amount.

Bliss told KCTV5 that accusation was ridiculous and untrue.

KCTV5 did deliver the three single dollar bills to Bliss that day.

“$3 dollars isn’t going to kill me,” Bliss said. “But I just don’t like people stealing out of my account.”

Bliss filed a complaint with the Better Business Bureau.

If you suspect something like this has happened to you, most credit card companies will refund you the difference if the restaurant itself does not. Policies vary, but here are a few tips to get your money back.