Pet Tech - Anti Bark Collars

Three weeks ago I purchased a Petainer Pet-850 anti bark collar from Pet Tech South Africa. My journey starts off by batteling to get my order from them, numerous email messages because they haven't got a telephone number to contact them. After eventually receiving the device it didn't work. Again I send a mail but up to date no responce. Please can you help, or at least advice people not to buy at that company.