Hi Betlav,
We understand you've been experiencing some dropped calls. Does this seem to happen in certain locations? We recommend following the steps in this article to try and resolve this issue: If you can't make or receive calls on your iPhone.
You may need to update your software if it's outdated. Be sure to create a backup before updating your iPhone. These articles will help:
How to back up your iPhone, iPad, or iPod touch
Update your iPhone, iPad, or iPod touch
If it continues after those steps, contact your wireless carrier to look into this further.
Cheers!