Google Play Services has stopped

On my Samsung Galaxy A6 I keep getting the message ‘Google Play Services has stopped’ Whatever I try to do this message keeps appearing and I cannot get rid of it. I did manage to get into the app, but on trying to uninstall updates got the message ‘Uninstall unsuccessful’ At the moment this device is totally unusable. ‘Send Feedback’ does not work. I am unable to access the cache to clear it, so none of the fixes I have seen in previous posts seem to be available. HELP please!!