The View class, at the top level of the Addon domain, has a namsepace that does not match the autoloaded directory. Specifically, the namespace include Helpers while not being located in a /Helpers sub-folder.
see src/Addon/View.php
<?php
namespace GiveBitPay\Addon\Helpers;
class View {
//
}
Instead the namespace should simply be GiveBitPay\Addon.
<?php
namespace GiveBitPay\Addon;
class View {
//
}