I'm not surprised you have problems with the OBiON app. It does work for me in a very clunky way, but many report having problems with it.
If you do decide to go with voipcheap or many other betamax providers, then you need to convert national numbers to international format. If you wish to dial 07123456789, then voipcheap expects to receive 00447123456789. This can be done like so:
Physical Interfaces > LINE Port > InboundCallRoute:
{ph,vg1(00447123456789)}
Rings the OBi110 Phone Port and your mobile phone.
Voice Services > Gateways and Trunk Groups > Voice Gateway1 >
Name: voipcheap
Access Number: sp1(sip.voipcheap.co.uk)
DigitMap: (<0:0044>7[1-9]xxxxxxxx|00447[1-9]xxxxxxxx|00xx.S4)
AuthUserID: your accound id
AuthPassword: your account password
To additionally allow dialling mobile and international numbers from the OBi Phone Port via voipcheap add (Mvg1) like so:
Physical Interfaces > PHONE Port > DigitMap:
([1-9]x?*(Mpli)|[1-9]S9|[1-9][0-9]S9|911|**0|***|#|(Mvg1)|**1(Msp1)|**2(Msp2)|**8(Mli)|**9(Mpp)|(Mpli))
Physical Interfaces > PHONE Port > OutboundCallRoute:
{([1-9]x?*(Mpli)):pp},{(<#:>|911):li},{**0:aa},{***:aa2},{(Mvg1):vg1},{(<**1:>(Msp1)):sp1},{(<**2:>(Msp2)):sp2},{(<**8:>(Mli)):li},{(<**9:>(Mpp)):pp},{(Mpli):pli}
Using the above setup, you dial mobile numbers in the standard 07123456789 format and the digitmap will convert to international format for you. The digitmap also allows for normal international dialling - 00xx.
You might notice that voipcheap and some other betamax companies are not totally upfront about their costs. For example, if you buy £10 credit from voipcheap, then you will be billed for around £13 as they add on VAT and a small handling charge after you choose the £10 credit option. Having said that, they are still very cheap for UK mobile calls and for most international routes, plus some free days to some destinations.
Drgeoff – I'll have a look at FreedomPop - might be interesting ...