Product item page keeps saying product not found and when I press checkout I get errors

Call to a member function getPaymentMethods() on a non-object

$this->page['attributes'] = Attribute::all(); $this->page['paymentMethods'] = $this->order->getPaymentMethods(); $this->page['items'] = CartClass::getContent(); $this->page['subtotal'] = CartClass::getSubTotal(); $this->page['total'] = CartClass::getTotal();