PHP Fatal Error: Call to undefined method

I have download the module and find out that getCollection method is not exists in the Igorludgero\Correios\Model\ResourceModel\Cotacoes class. Seem like a bug in the module. Usually getCollection method used in the regular models, not in the resource model. Try to contact the author of this module, or fix it by yourself - change this method:

public function __construct(\Magento\Catalog\Model\ProductRepository $productRepository,
                            \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
                            \Igorludgero\Correios\Model\ResourceModel\CotacoesFactory $cotacoesFactory)
{
    $this->_storeScope = \Magento\Store\Model\ScopeInterface::SCOPE_STORE;
    $this->_scopeConfig = $scopeConfig;
    $this->_productRepository = $productRepository;
    $this->_cotacoesFactory = $cotacoesFactory;
}

to this one:

public function __construct(\Magento\Catalog\Model\ProductRepository $productRepository,
                            \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
                            \Igorludgero\Correios\Model\CotacoesFactory $cotacoesFactory)
{
    $this->_storeScope = \Magento\Store\Model\ScopeInterface::SCOPE_STORE;
    $this->_scopeConfig = $scopeConfig;
    $this->_productRepository = $productRepository;
    $this->_cotacoesFactory = $cotacoesFactory;
}

I think this should work, because we just changed the resource model factory to the simple model factory. In the all places this factory is used as a regular model factory.

This changes exists since the 77473019194767fd482c8b8d47874a12596a234e commit, when the regular model was changed to the resource model factory, and I dont imagine how it can work for the other users without errors after this "update".