Credit Card Error - What Would You Do?

We use credit cards for almost all of our purchases - we pay them off monthly but it's a nice way to keep track of our expenses, and to earn points. In October, my husband used one of our credit cards to pay for some take out food at our favorite local restaurant. When I got the credit card bill in November, I noticed that the take out restaurant charged us twice - one for our purchase and a second time for an amount almost double that amount.

I disputed the charge with MasterCard - not an easy thing to do actually. First, you have to fill out a tiny form on the back of your bill. Then, we got a letter that had to be signed and faxed back within three days. Finally, two months later, we were told that we were getting our money back as a credit.

Last week, I was shocked to open my mail and find a letter that stated they were charging us the amount again. Apparently, the restaurant supplied a signed credit card slip. A quick scan of the slip copy they sent us showed us that it was obviously someone else's signature and order - it even had a different name and phone number. But, since the restaurant provided a slip, it was considered my fault regardless of whose signature was on it.

After complaining to the credit card company, they credited me the amount but would not find the restaurant at fault - it was a courtesy credit, they said. I've really nervous to use my card now - what if it was fraudulently used again - for an even greater amount? And, I'm really frustrated with the restaurant.

I wrote letters to the credit card company and the restaurant. No word yet from either of them. Has anyone else had this happen? If so, what did you do?