Being treated unfairly

I Am not happy with the service at the Replay store at Gateway ,I did lay bye an item in April the total of the was R2600 ...R2100 was my 1st payment to my knowledge and according to my receipt I was suppose to pay R500 remaining balance by July how ever due to unforeseen circumstances I ended up in hospital due to me being 7 months pregnant at that time and was unable to attend the store so last month when I did go to pay the remaining balance and explain my situation they were being inconsiderate and refuse to co-operate with me spoke to the manager and was told that I need to pay another R1550 and yet the item costs R2600 and I already paid R2100 so I told him that it's fine then I will cancel the lay bye but was told that I cannot cancel it ,and even if I do cancel it dey can't refund me ....I with understand if the price of the item I chose increased then I would have understood but now they just being unrealistic and I feel like I'm being ****** by them ..