They are the worst Voice and SMS connectivity service I have ever used. I signed up with them and received no customer support from the very start. When I would have a problem, I'd often be told that they didn't know why it was happening and leave me on hold. My calls were not being transferred on about 50% of my calls and about 20% more of my calls would be disconnected before they made it thru to the customer.
When I called into support for help, they told me they would have a tech look into my account and they would call me back. They didn't call. I called back in a week later and was told that all phone companies were having problems with too much business so calls were being disconnected - including the regular phone company. I had to reiterate to him what I was hearing and he said yes, they were just too busy and had too much business for all of the calls to transfer thru.
I had a $300 credit on my account because I pre-paid and then the next day I had a $319 deficit in my account. I called in to see what had happend and they told me that I had a call connected for 2 days. I listened to the call and it was a call that never got transferred thru due to the broken system however I was charged $600 for the 2 day call.
The woman I talked to immediately credited me for that call. I have requested a credit for my balance.
Do not use this system, there are so many frustrations and they have no idea how to fix their own problems.