Quick to remind of my payment but to respond if I have query.

Cell c handed my account offer to nimble collection. After they phone me telling cell c handed my account to them immediately j made arrangements and start paying them off. They appear on my credit score stating that I don't pay. I do have proof. My score drop few point of them saying I don't pay but do pay. I send them email. They reply weeks after but they cn phone me and send emails very quick to say I must pay. They messing with my credit score.