Consider this revision:

The sentence you mentioned is still adequate English. I have seen many ads on this site with rather basic mistakes: wrong capitalization, inappropriate tense, spelling mistakes, sub-standard wording, use of slang, and so forth. Do you think those are the kind of ads you would expect of an English tutor? These blunders which i just outlined swarm the pages of QL.

There are so many errors in your own wording. Some are subtle: others are obvious.

How can you help someone prepare for IELTS and other language tests when your own English is far from adequate? Why are you so reluctant to disclose your qualifications? How can someone care to give you a try when they do not even know your background?