Muliple developers in same visual studio project

Hi,

We are having an issue with pull and merge when more than one developers try to push changes to the same project and same branch, this comes when we use large visual studio solutions having more than 10 projects in same solution. Comparatively small projects are working fine and we use visual studio 2012 with GitExtensions-2.48 and GitSccProvider. Also when the release engineer try to pull the changes from the developers most of the times we have to delete the local repository and clone again because pull branch also not working properly, it shows the branch has merged with the new branch name also but the source code is still older one. Do you have any recommended extension for visual studio projects and do we need to switch to command line option rather than GUI extensions ?