Letmeloginthanks888

I have multiple submission receipt/IRmark from my accountant due to doing an amended submission when online didnt update but getting told i havent submitted, worse still ive had a £100 fine even though i submitted well before the deadline. Accountant uses their own software and has done for years, have the receipts and unsure who I should contact. Tried appealing which i did two days before the appeal deadline but got a letter saying I missed the appeal deadline, its been very stressful.