Based on your post, that sounds like a coherent argument. Failure to meet an employer's expectations is not misconduct. What did the termination letter say, if anything?
What do have to lose by appealing? Good luck!
In Georgia, if an employer terminates an employee "for cause", the Department of Labor will evaluate the following factors in order to determine whether to award unemployment benefits:
1) The manner in which the rules, order, instructions or duties were made known to the employee, including, but not limited to: whether the rules were posted or otherwise published prior to the incident that lead to the termination;
2) Whether a violation of the rules, order, instructions or duties actually occurred;
3) Whether the employee failed to discharge the duties for which she was employed;
4) Whether the violation or the failure to discharge duties was a result of the employee's fault, intentional conduct, conscious neglect, or misconduct;
5) The extent of the infraction; and,
6) The impact of the infraction on the business' operation.
Based on the scenario you describe, you may want to consider explaining to the Dept. of Labor that 1) the employer agreed not to contest your unemployment benefits; 2) Even if you did not properly discharge your duties, your misconduct was unintentional.
Ultimately, the best thing for your to do is to contact an Atlanta unemployment benefits attorney.