You mean calls and texts were working OK before now but when you changed your internet settings they stopped working?
I would suggest that you delete any internet settings/APNs that you have configured and then see if calls/texts work.
If not then you need to deal with that issue first.
Do you have a connection to the 48 network?
If not then what exactly is happening?
Do you have roaming/data roaming enabled?
One way or another you need to get basic connectivity and calls/texts working before doing anything else.
Once you do get basic connectivity/calls/texts working then you can configure your internet settings afresh.
Some of the guides on this site are wrong but these instructions are reliable if read and followed carefully:
Hope this helps.