PPI reclaim on a partially settled account

[jamiet82]

Back in 2010 I agreed and paid a partial settlement for a capital one credit card debt that was passed on to a collections company. I recently contacted Capital one to reclaim my ppi, today capital one have written to me upholding my complaint. But have said in the letter a percentage has been credited to my closed account and the rest is being sent to me as a cheque.
If I had an agreed partial settlement can they reopen the account and pay off the remainder of the balance?
Would be grateful for any advice.