What to do if a buyer wants a different service?

[teamandromeda]

Hi! So I´m super uncomfortable since the buyer ordered A but suddenly wants B, which I don´t offer. He described B as well with instructions to receive part of the information to complete A so there wouldn´t be any issue. I asked the buyer to either hand over the information right away to complete the order in the way I normally do for each customer, or cancel the order. So now he made a dispute with the comment that I´m not able to do the job. Any suggestions what to do?