Difficulties to to parse XML Elements from $response

[stevang]

I have difficulties to get the xyz and timestamp element. What am i doing wrong?
echo $response->body->content-xzy->xyz;
does not work. i would realy appreciate some help how to get these values from the response.

this is the first part of the xml response containing the needed values

Httpful\Response Object
(
    [body] => SimpleXMLElement Object
        (
            [content-xyz] => SimpleXMLElement Object
                (
                    [xyz] => 123456789012
                    [timestamp] => 2017-04-24T20:22:52Z
                )

        )

    [raw_body] =>