Sorry to hear about your refusal I understand how your feeling at the moment.
As suggested earlier it does no harm to submit a letter requesting reconsideration, you never know it may work.
You're not even borderline on the earnings so it would appear you have been badly let down by your agent which is another lesson to everybody here.
Your partner will have the appeal forms so be aware that they will have to be submitted on time to HMCT here in the UK. If you are requesting an oral hearing you will be given a date to attend but please be aware this could take a long time.
The decision will have been made on the basis of the information you provided and if you have not satisfied them on earnings then they will refuse.
You may wish to take advice from an immigration expert here in the UK as it may be a better course to submit a fresh application with all the correct documentation.
As a guide if you follow the appeals route it could take 6 months minimum before you are given a date.
I wish you well.