Wrong Reservation

My sister made a wrong reservation for ahotel in Prague. My sister and I  had planned  to travel to Prague when she visits me in Europe. We decided to go to Prague because it is really beautiful and women generally love the city so much. I wanted to make a reservation on my own but something went wrong when I tried to book a hotel room. My credit card didn't work the first time. I tried again, and the price of the hotel room  went up over 50 Euros. What a funny situation! I then talked with my sister and we decided to book another hotel. When I had tried to book another hotel that we both chose, my card was blocked again for some reason. I suppose it is because of security reasons which is really stupid. Korean banks block nearly everything. So, I asked my sister to make a reservation for us. However, she made a mistake when she booked a hotel room. She booked for only one person instead of two people. I sent an e-mail to the hotel that we made a mistake and asked what we have to do to make it right . I hope we will just pay an  extra cost and  everything will be fixed.

Wrong Reservation

My sister made a the wrong reservation for a hotel in Prague. My sister and I are planning to travel to Prague while when she visits me in Europe. We decided to go to Prague as it is really beautiful and women generally love the city so much. I wanted to make a reservation myself on my own (myself, by myself) but something went wrong when I tried to book a hotel room. My card didn't work the first time in the first place. So I tried again, and then the price of the hotel room just went up over 50 Euros. What a funny situation. So I talked with my sister and we decided to book another hotel. When I had tried to book another hotel that we chose to stay in, my card was blocked again for some reason. I suppose it is because of a security reason that is really stupid. Korean banks block nearly everything. So, I asked my sister to make a reservation for us. However, she made a mistake when she booked a the hotel room. She booked a room for only one person instead of two people. I sent an e-mail to the hotel that we made a mistake and asked what we have to do to make it right (to sort it out). I hope we will just pay an extra fee [instead of fee you can also say charge] cost (we will be charged a bit more) and then everything will be fixed.

Your english writing is really good!  I just corrected some grammar and made it more natural sounding.