Probably a repeat but
Debt 1 & 2
Took notice of change of my circumstances, listened and took reduced payments without penalties being applied. My circumstances changed and I have increased payments. Still not at the original amount but still no penalties and they will get full payment albeit over a longer time. Haven't CCA'd them as they acted responsibly and fair.
Debts 3 & 4
Took no notice, ignored all correspondance and increased the stress of what was already a difficult time. Refused to acept reduced payments (I still made them) and carried on adding interest and charges. They don't have valid CCA's and are getting nothing and won't get anything.