ESA no initial payment

Hi guys

I need some help, i applied for esa on 8th April as i am going through bad anxiety and PTSD. After few days they sent my statement back and ask for doctor's note which i sent on 18th April.

On 19th i got sms from Jobcentre that they have all information and they will contact me with the decision.

I also received the letter from Jobcentre saying that i am pleased to you that we can pay esa form 8th April you will get £84 a week etc.

I rang Jobcentre on 25th April and i was surprised when they said they have not received my sick note and i need to ring on Monday to find out.

I rang today and got another surprise when they said you need to send the ESA50 form back then we can release the payment.

Can anybody tell me if this is true i am totally confused and upset as i cant fill this ESA50 as its too difficult. I made an appointment with local cab but the date is too far and i dont know what to do.

Thanks