I've had similar issues - so much so that I've created Resgen[0] just because it was tough getting call backs. It turns out I really needed to tailor my resume to each job and it resulted in a lot more call backs.
10 free resumes per month seems too generous. Also, $7 is very low for a paid plan, when your users are likely to churn as soon as they find a job. If this tool is really as valuable for job hunters as it aims to be, they should gladly pay three times that amount.