Bad service no accountability

Settled their account on 23/05/2022 and now they claim to not have received payment yet all other payments prior reflect, yet the one to zero my account mysteriously goes missing your recoveries department is the worst I've sent through proof of payment and want a settlement letter and information updated on ITC. I've never dealt with legal trace ever but now that the account is settled im getting calls from them what's going on there?? Please fix this coz my next step is the ombudsman