I had no alternative but to use my mobile phone to place the call and today I have received a bill, which includes a charge of 17.95 for this 17 minute call, see: https://dl.dropboxusercontent.com/u/22679018/UAE%20Call%20charge
After the call, we investigated why the app had not worked and it turns out that this was due to the version of the app I was running not being up to date.
We were not notified that updating to the latest version of the app would be required for service continuity. Aside from the personal expense I have had to go to to place this call, I no longer have confidence in your service. Being able to place VOIP calls is essential for our business. I am requesting as a bare minimum that the cost of the call detailed above be reimbursed to us.
If this is not resolved to my satisfaction, I will be forced to look at an alternative provider