Bhan Thai

I got a meal to go on the evening of August 2, 2020. The meal was $15 and some change. I remember tipping about $2 bringing the total close to $18. I signed the receipt only authorizing this amount. When I checked my bank account on August 6, 2020, I noticed the restaurant charged me $39.50. I immediately messaged them on*** because they were closed, so I could not call them. They apologized and said they would fix it. I messaged them about two days later asking for an update. They told me they were busy but would get to it. A few days later the issue still had not been resolved, so I messaged them again. This time my message was ignored. I was never rude in my messages. I simply want my money back and an explanation of what happened. This is an important issue that could be handled quickly. I've worked in restaurants, and if this happened at my place of business, it would be taken care of immediately. Yet, I have been waiting for two weeks for this to be resolved with no indication that it's going to be handled any time soon. I reached out to my bank, and they said they would investigate it. It took them about ten business days to do this. I spoke to the bank today, and since the restaurant is the only one with the signed receipt, the bank cannot do anything until the restaurant provides them a copy of it. I really did not want to have to resort to filing a formal complaint, but this seems to be the only way to get the restaurant's attention.
Product_Or_Service: FOOD