Worst support during covid 19

Due to the covid 19 I phoned Truworths the end of March and advised them that I will not be able to pay the total instalment due from April for the next 3 months. I even sent them the letter we received from our company. April came and I got a statement from the full instalment due, when I phoned them I was advised that it is automated they cannot change it but it I made an arrangement it will be in order. I then only paid the amount I advised. I just got my statement for May and I am in arrears and they charging me interest. Once I am done paying my account they can forget about having me as a loyal client,due to their incompetence.