Unable to match the margin in the table of contents

Question

I have used this code from how-can-i-add-abstract-and-acknowledgement-pages-into-the-table-of-contents to add abstract and acknowledgement. However, I am not able to match the chapter titles with the existing margin format of other chapter titles.

Like shown in the picture!

My code after title page and before introduction chapter is given as;

\pagenumbering{roman} 
%\shipout\null
%\stepcounter{page}
\cleardoublepage
\chapter*{Acknowledgement}
\addcontentsline{toc}{chapter}{\numberline{}Acknowledgement}%
\lipsum
\chapter*{Abstract}
\addcontentsline{toc}{chapter}{\numberline{}Abstract}%
\lipsum

%----------------------------------------------------------------------------

\tableofcontents
\listoffigures
\listoftables

Please let me know how to correct the margin in TOC. Thanks in advance!

Answer 1

I added a bit more of dummy content using the duckuments package. You get the correct alignment if you drop the \numberline{} in the last \addcontentsline argument.

\documentclass[]{report}

\usepackage{duckuments}

\begin{document}
\pagenumbering{roman} 
\cleardoublepage
\chapter*{Acknowledgement}
\addcontentsline{toc}{chapter}{Acknowledgement}%
\blindduck
\chapter*{Abstract}
\addcontentsline{toc}{chapter}{Abstract}%
\blindduck

\duckument

%----------------------------------------------------------------------------

\tableofcontents
\listoffigures
\listoftables
\end{document}