Problem with automatic table of contents

[pogonoforysci1]

Hi, I'm trying to write my PhD thesis at the moment and I have a problem with automatic table of contents. My chapter titles are quite long so I have to separate them into two lines using enter (+ that is how chapter titles are formatted in these from my institute) (picture AAA). That causes a problem when I create a table of contents because chapter headlines with an enter used in them are being recognized as separate and not as parts of the same headline. Is there a way to solve this so in the table of contents I would have

Chapter 1: Introduction.......................page number

instead of

Chapter 1:.........................................page number


Introduction...................................... .page number

I'm not even sure what I should be looking for in google to sort this out so any help will be appreciated