User Verification Error/Please Help!!!

On a mobile device if a user tries to sign up they are sent a verification code to their email and the issue is when a user goes to there email to retrieve the code and then returns to the app the sign in flow resets. So user loses the option to enter code. If they try to sign up with that email it will tell them there account needs verified by the code and that it was sent. If they try to sign up it will tell them an account already exists with that email. So they are basically locked out at that point if they dont have another email to try again. Please add a way for users to enter verification code in the sign in flow even if they have closed out the app and reopened it or maybe add a verfiy email button link users can click from their email that will automatically verify the account instead of the code. This is a serious issue that iam losing lots of customers over please help