4 months is a long period. They issue EIN in 45 business days, which is around 2 months. Call their support and ask them to check in the System. If the number is not ready, your fax/mail did not go through and you definitely need to resend it. It is possible that EIN was assigned for your entity, it just got stuck somewhere in post. You have to call and ask them over phone, they will help you.
I got EIN last week after waiting for︀ 2 months.
IRS domestic support for EIN 180008294933