haber vereyim dedim seni unutmayan

 my try

 I told you ,let me inform him/her ,don´t forget

 Don´t you forget I said let me tell

My try

thanks!!!

 I think a little typo there.

"I thought I should let you know, before I forget it."

thanks.

 So does ´haber vereyim dedim seni unutmayan´ have any meaning then? 

 I think No.

 So there is no such word as ´unutmayan´ in Turkish?

yes there is, and it means "the person who does not/did not forget".

but this particular combination of words makes no sense.

 Thank you.