Downloading/Buffering stops after a while

Since a long time I've had a very poor internet. I decided to get 4G internet since it provided 10 times more download speed than my previous internet. After using it for a while, I realized something kept happening. I can't download anything with it, a few seconds after I start downloading something, it starts slowing down and ends up completely stopping the download, happens with Chrome, Mozilla and IE. Also, loading videos stops after a while, as I change the quality of the video, they load for a few more minutes. This does not happen with any other internet I use.

I'd like to know if anyone knows why this is happening, and possibly, if anyone knows the fix.
Thanks~