MyJar Equifax report FOS advice needed

Hi everyone I'm looking for some advice please if possible with a extremely long ongoing issue with the payday loan company MYJAR 😡 In 2015 i noticed Myjar had listed a account in default on my noodle credit report and made out I had only just started this loan and missed payments etc on emailing the company it transpired to actually be from a payday loan back in 2012 and they agreed that if I cleared the balance in full they would update the report to show settled with the correct dates etc I agreed to settle if they removed all there extremely high fees which they agreed to do so I paid it all off in full the same day. I had written confirmation it's settled and closed and noodle would be updated which it was. This is now where my troubles started because 3 months after the account was settled and closed someone at Myjar decided to now list the account on Equifax and also £500 in arrears and defaulted :mad: I was gobsmacked I complained straight away and they replied saying how sorry they were and I don't owe anything etc etc they also stated in writing that if the account is found on Equifax it will be removed as part of the agreement when it was paid off. Over a year later it's still on Equifax and have updated it to show 1 month in areas and show I missed my first payment in 2015 ??? So it will stay on my report until 2021 which is disgusting considering it was taken out in 2012. They are 1000% refusing to remove the account and are now stating the only way to update this account to show the correct information would be to now issue a back dated default to 2012 so it falls off the report in 2018. I find this very unfair as again I have in writing from the company that no default notice was ever issued and if it had been done it would have been incorrect so I don't understand how they are allowed to do this 4 years later and settled ? I've also complained to the financial ombudsman service who have replied tonight agreeing with Myjar that the only way forward is to list the back dated default even though I've issued him with loads of eveidence I'm very unhappy with it all. Dose anyone know if I can take Myjar to court to have a judge go over account and the way they have handled the situation and with my evidence I believe I would have a very good case ? Any help or suggestions would be fantastic as im slowly loosing the will to live thanks everyone