Here is how to delete a service app with Power Shell
$spapp = Get-SPServiceApplication -Name "<Service application display name>"
Then to keep the data
Remove-SPServiceApplication $spappOr remove DataRemove-SPServiceApplication $spapp -RemoveData
If the above does not work you can try this command(Dirty Method):
stsadm -o deleteconfiguratio nobject -id <ID>
Where you can change "<id>" to $spapp (Suppose to, did not test it)
you can also run get-SPServiceApplication for a list.