Hi there and that’s an exciting development in your job search! It’s very acceptable to follow up with a friendly enquiry after 48 hours. If you get no response, follow up via email in another 48 hours and change the angle of your enquiry slightly, for example by attaching your CV again for their convenience. If everything is still dead quiet after that, I suggest a final phone call a week later with a direct question, asking if the position is still open and if you are being considered for the position. If you don’t have a contact number, then an email will have to do. I wish you much success and hope you hear from them soon!