Arrow Suspended account 12 mths on mark credit file with 6 late payments ANY ADVICE

[seaweed99]

I have a debt from 2012 with shop direct which never defaulted but it should have. The account was passed on to Arrow who were rying to increase my payments, so following a thread on here I asked for the CCA agreement and made a complaint that the account should be defaulted in 2012. In March 2018 they confirmed they do not have the CCA documents and my accounts would be suspended which they were. In april 2018 they placed a late payment marker on all three accounts on my credit file. I complained and stated they accounts are suspended how can I miss a payment, they agreed to remove them, they removed them from 1 account but not from the other two. A year later they are still have an affect on my credit file becuase the accounts are still open and it showing a missing payment marker from April 2018. After numerous emails and calls they swore they have instraucted the department to remove it. A few weeks ago I checked my file as I am desperatly trying to get my life on track and it was still there, I rang them up and a few days later received a compensation cheque for £100 and a detailed letter explaining it was their error and it was now sorted. July I checked my file and they have not removed it and now added a 6 missing Payment marker to all three accounts having not reported on these for a year, Is there anything I can do ?? where do i stand with this, Ive been in a dark hole for 6 years and this has killed my credit file. Please help if anyone can advise i would be gratetful