DWP not receiving adequate uploads

I recently received my bundle from the DWP but it was missing my 'reasons for appeal'. The DWP assert I did not give reasons for my appeal and has based its predictable decision on all the facts except my reasons.

I did in fact submit it to HMCTS but for technical reasons it came up blank on their system but I didn't know until a couple of weeks after. I immediately submitted it again but it seems my bundle was sent to the DWP before this.

Has anyone else suffered anything like this and will I have difficulty in getting my 'reasons for appeal' submitted, with a new response from the DWP? HMCTS have emails from me about all of this.

HMCTS assure me it has the document but say it will be up to the decision maker to decide if it was submitted in time. I voiced my deep concern over this because my appeal hinges on that letter. But I can show it was in fact submitted in plenty of time and have an email exchange to print off as proof. I'm just wondering if the DWP doesn't always bother to check if all the papers are in order. Many thanks.