Problems with VOIP using Linphone app

I have decided to create a VOIP account with Afrihost. It's been more than a week now since I spoke to a consultant to assist me with reactivation of my account. I've been unable to connect with my voip account. I've uninstalled and reinstalled Linphone but continuously loses connectivity. Please help. I want to cancel my expensive landline but cannot if VOIP is so unstable.