If you are adding a channel to the myservices.xml file, you need to add an action statement to tell it what you want it to do.
For example...
If you delete an adult channel and have auto scanning running, it will bring it back! If you want to keep the channel deleted, you need to add a 'remove' action to the channel, i.e.
<channel action="remove" service_id="041b" name="The Adult Channel" service_type="01"/>
For example...
If you have a low signal and every time you do a scan, you don't get Sky One. But, if you manually add the channel data to your services file, you get it ok. But every time the auto scanning runs, it doesn't see it and removes it from your services file. So you need to add an 'add' statement to the channel, i.e.
<channel action="add" service_id="0011" name="Sky One" service_type="01"/>
You don't remove the services.xml file. Myservices.xml is used in addition with the services.xml file.