Viber 2 different Activation Codes

Amazing! I am still trying to activate Viber app on my old iPhone 5s. I do receive sms code 95xxx4 but get error: invalid or wrong code. By the phonecall I get similar code but different: 95xxx7. Still wrong code message. There is no direct contact or chat wirh support and I am pulling my hair out of surprise that Viber can not be activated on this iPhone?! Any help would be appreciated. Maté