citet flat out refusing to work

Question

appologies if i get the question format wrong, this is my first post.

so im writing my thesis at the moment, and all of a sudden natbib seems to stop working entirely. im not sure why, but all of a sudden citet just reverts to bracketed number..

the format i need is that citep appear as bracket numbers, i.e. [1;2;4] etc. and that citet appear as NAME (YEAR), but no matter what i try citet print square bracketed version..

so i tried to create a dummy document with nothing in it, and citet seems to be working the same way.. what am i doing wrong here guys?

\title{natbib issue}
\author{
        James
}
\date{\today}

\documentclass[12pt]{article}
\usepackage{natbib}
\begin{document}
\maketitle


\section{citep}
This is how citep is working\\
...As seen in previous work \citep{bibreference}.
\paragraph{}

should be\\
...As seen in previous work [1].

\section{citet}
This is how citet is working\\
\citet{bibreference} reports that...
\paragraph{}

should be\\
Abbasi et al. (1999) reports that...

\bibliography{paper}
\bibliographystyle{plain}


\end{document}