Samsung Galaxy issue

This is the last place I would think of to ask for technology help; not because I don't think people here are not knowledgeable, it is just the last place I would think of, however I have ran into a very annoying issue that I have spent days researching and trying to fix however cannot come up with a solution.

The Army has recently moved me to Germany and I brought my Samsung Galaxy S4 with me. I got this S4 when I opened a contract with Verizon about a year ago back in the US. Now that I am living in Germany I bought a German SIM card from Vodafone (for those of you familiar with European cell phone providers) and just buy the pre-paid minutes/texts and data because German cell phone contracts are outrageous. So far this has all gone well and I can call, surf the web, and text.....well, kinda text.

I have an issue with my phone where anytime someone texts me it puts the country code for Germany (+49) in front of their number and that makes it so I can't text them back unless I delete the text message and create a new one. So I might have their number saved in my phone as 0151 12345678 but as soon as they text me the phone makes it +49 0151 12345678.

Basically I want to know how to disable this feature in my S4. Hopefully there are some other Europeans here that have the S4 and can tell me if they have this issue.

Thanks