How to satisfy the Visa Officer

Could you offer me an advice on this matter? I received a letter from VO regarding the visa officer is not satisfied with my IELTS scores and given me the chance to provide an evidence that I consider germane.I've been working in one of the English speaking countries and strong educational background and working experience more than enough. Every point of communication here for me is just in English. Besides a mian career, I am working as a part time teacher and I have given my course in the class purely in English.I actually don't prefer to re-sit IELTS agin without preparation. My previous mistake was I did not put an effort in preparation when I took IELT first time because of my very hetic work schedule and heavy workloads so attained merely 6 band. So as to tackle the current critical situation within short period, I must act productively and daren't not to make any mistake to pay high value. In the letter ,the office said that I should provide any evidence to disabuse the conclusion from VO.

I would appreciate an advice from you how to make the visa officer satisfy regarding providing the satisfactory evidence shortly.Immigration to Canada is seriously life & death matter for me and my family.Please help me out.

Thank you.