DISGUSTING SERVICE EVER!!!

so I took furniture with this furniture store in the year 2020 in October and paid my first installment in the month of November till January when I was called by a store consultant stating there was a mistake with the paper work I should go back to the store to redo my account which was confusing, so I went to the store and I was told I would then get my money back for the past months which I had the account and later I was called they advised they will only refund me 2500 then the rest will go towards the account, I agreed and all was done, now to my surprise i paid 18000 on the account and that time my balance was 22000,then the same Monday they debited their normal installment, shockingly today I called them asking for my balance and am being told its 3000 and that's an estimate amount which is really confusing and shocking because according to my understanding I am not owing these people a single cent as I have a credit on the account, the consultants when you call in they sound clueless and lets not talk about the store consultants ,they are very rude all they know is to play loud music and only one agent takes payments, SHOCKING DISGUSTING SERVICE,I REPEAT I AM NOT OWING YOU GUYS,I HAVE A CREDIT ON THAT ACCOUNT...OOOH LORD I REGRET THE DAY I TOOK FURNITURE IN THIS STORE.