Regarding the first issue with the upload limit being 7 MB, we're getting this information from php.ini that sets up the limits. In order to increase this limit, you would need to change the upload limit value in your php.ini file on your server and you can also add 2 lines of code in .htaccess file in the root of your website:
upload_max_filesize = 7M
post_max_size = 7M
Add the below to your .htaccess file in your website root directory:
php_value upload_max_filesize 7M
php_value post_max_size 7M
Change 7M to desired amount in Mb.
These approaches might not work though if you are on a shared hosting.
In that case, you would have to contact your web hosting provider to increase the limit for you.
Regarding number 2, do you get any errors? Are the files being saved in the media library? Can you access them via the links from media library?
You can also contact me directly via firstname.lastname@example.org and I will try my best to help you resolve your issues.