Account fully paid up! No paid up letter since

I have a huge problem I am sitting with , my account was handed over since I could not afford to pay old mutual for some time , fine CSS contacted me to make arrangements with me on how I maybe able to settle account on a discounted rate and I did that in January around the 25th or so , till this day I am sitting with a issue of a paid up letter that I have not received from old mutual nor that CSS collecting company where they handed me over , no communication I constantly have to do follow ups my emails are ignore , lady by the name of poppy who works for that CSS company does not even bother to reply to me anymore , I made sure I keep to my end part of things but them ? Now that the account is settled I no longer matter ?