Home phone not working

I switched from Vodafone to Virgin 2 weeks ago. Broadband is working but home phone has engaged tone when dialling and goes straight to voice mail when called. I have contacted Virgin daily to try resolving.  Did all the usual things rebooting etc. Last Wed I was told my phone was not compatible and Virgin sent replacement but still the same issue.  They also cancelled the order and setup again. At this point I just want to cancel and transfer back to Vodafone but concerned that whatever Virgin has done with phone line will cause issues when transferring back to Vodafone.