Don't use the starter service (it's a "special" B4A-service), use another one (just add one) and use
Sub Service_Create
sNotif.Initialize
sNotif.Icon = "icon"
sNotif.Vibrate=False
sNotif.SetInfo2("MyService","Service Running","...",Main)
sNotif.Sound = False
sNotif.Notify(1)
Service.StartForeground(1,sNotif)
End Sub
This will start your service as a ForegroundService which will be kept. Bad thing: There will be a notification.
Another hint: Your php call looks very fragile! Everyone can send a complete SQL-statement (even "Delete from listadocambios" which deletes the complete table).