Hi, this is Jim, thank you for the question - I will resolve this for you.
Sorry to hear of the issue. If you have refunded this lady in full, I am not sure why she feels that she is entitled to more money. The courts would only ever put her in the position she would have been in had her consumer rights not been breached (as an example).
If she is claimant that she was inconvenienced or stressed, she could ask the court for compensation to reflect that but it would have to be serious enough to warrant court action and an award from the court.
If she starts a claim against you, you will receive court documents (a response pack) which you must complete and return to the court. It is a tick box exercise for the most part and there is a short section to write a defence which is easy enough though please feel free to come back to this site if you need any more help. A claim will also take 6-12 months to be decided at court. If you lost then you would get 14 days to pay the judgment before the claimant can enforce the order, and 30 days to pay in full before it is registered with credit agencies. The claimant cannot recover legal costs if they win, in a claim under £10K (a small claim), all they can claim are the court fees and interest.
I can assist you going forwards if it gets to the point they issue a claim. If her claim has no merit at all, you have the option of making an application (after you file a defence) to strike out her claim as having no merit. The court will grant an order of this nature if the claim discloses no reasonable grounds for bringing the claim or if it is an abuse of process. Again, I can help you with that if you get to that point.
I hope this helps and answers the question - please feel free to ask me anything else. I am not available for a call but I can answer anything else online for you if required.
Have a good day,