Okay
So what's your suggestion do I apply for visa or not?
I already scored 6.5 overall in ielts not less than 6 in each module
If you are able to give justification for the backlogs, and you are able to convince the visa officer that those backlogs are not indicative of how you are going to perform in the program you are going to do in Canada. When it comes to backlogs, the main issue is that your credibility of completing the program in Canada is questioned.
Many people have got backlogs in double digits and gotten a visa. However having backlogs makes you application more difficult. If you still want to go to Canada, then you will have to nail the SOP that you give and your profile has to be very good.
IELTS score is only to do with you understanding what is going to go on in your program. Your issue is your academic performance.