The OBiTALK portal is overwriting your changes with default settings. Use this method to make changes:
Make changes via the OBi Expert Configuration pages. From your OBi Dashboard, click on your OBi number and follow the prompts to get there. To change a value uncheck both boxes to the right of the value and leave them unchecked. After changing the values on one page, press submit at the bottom of the page and wait a few minutes for the OBi to reboot. Then move on to another page if required.
Change to these settings:
Physical Interfaces > PHONE Port > PrimaryLine: SP1 Service
Voice Service > Auto Attendant > PrimaryLine: SP1 Service
Greece seems to have various emergency numbers apart from 112. These are best dealt with in the Phone Port DigitMap and Phone Port OutboundCallRoute. Change as follows:
Physical Interfaces > PHONE Port > DigitMap:
([1-9]x?*(Mpli)|[1-9]S9|[1-9][0-9]S9|1xx|**0|***|#|**1(Msp1)|**2(Msp2)|**8(Mli)|**9(Mpp)|(Mpli))
Physical Interfaces > PHONE Port > OutboundCallRoute:
{([1-9]x?*(Mpli)):pp},{(<#:>|1xx):li},{**0:aa},{***:aa2},{(<**1:>(Msp1)):sp1},{(<**2:>(Msp2)):sp2},{(<**8:>(Mli)):li},{(<**9:>(Mpp)):pp},{(Mpli):pli}
The changes I have highlighted will ensure that any three-digit number starting with 1 will be routed to the Line Port / PSTN regardless of any changes to any other digit maps.
Edit: Let me know if there are any other numbers to be routed to PSTN. You know better than me what formats they take - number of digits etc.