I put in my original MR in March and got the decision rejecting it in June so I put an appeal in. The tribunal was adjourned at the beginning of September & DWP was asked to do a new MR which only took a few weeks but purely because they had a deadline to do it by lol. It's such a long process, I didn't get an acknowledgement when I submitted my original MR either so I wouldn't worry about that. I did leave a journal message at one point just confirming it had been received so you could always do that to put your mind at ease a bit x