I defualted on a loan where I received £80.50 and didn't ask for a faster payment with a fee of £19.50 but the loan then was £100. I made three offers to mini credit of £117, £150 and £266 and all I got back were automated emails, all of which I have a copy.
I had a special offer of £540 to close down my loan of £100 which is now with charges at £1079. I emailed them back to Andrew Parker who was supposed to have sent the email and also sent a couple more to OPOS but no reply to mine at all.
Was that the first email you sent to OPOS? I believe they are part of Minicredit. Did you pay them via their bank account as I wouldn't want to give them my card details.
Realise you have sorted your debt with them but be gratefull for a response from you.