I would switch to a well known provider for their "special&
VoipO provides free porting, I'd switch to their 2 yr special. VOIPo may increase price after 2 years, there will be better deals then.
If you mentioned VOIPo's offer, PP may offer to match their price.
When Myfax tried to increase my plan from $4 to $10, I told them I'd switch, they offered me to stay with $4/mo.