Selling plants in pots that are half the size as advertised

My mom bought me a Mulberry plant from Green Cloud Solutions as a gift. The Plant cost R119.99 (for a 6 litre pot) and the delivery was R125. She requested her initial signup coupon as it had already expired and they sent her a R10 coupon voucher instead. The plant arrived and it was suppose to be in a 6 litre pot but arrived in a 3 litre pot. When she wrote to Green Cloud Solutions, their response was "After reviewing the product description, I noticed that it mentions a +-6L or +-10L pot size. If you are not satisfied with your purchase, we would be more than happy to offer you a refund. Please note that the cost of returning the item will be your responsibility."

My mom responded with "I bought this plant as a gift for my daughter so I will not be returning it as I have already given it to her. Even if I did it return it, it would be foolish because of the cost of the courier fees both when purchasing and returning the plant would be more than just keeping the plant. That being said, the error was on your side - advertising a 6l pot and not delivering on it. So, in actual fact, the costs should be borne by you. I would appreciate you refunding me (back to my credit card) the difference of what I should have received as per your website (a 6 litre pot) and what I actually received (a 3 litre pot - 19cm diameter at the top)."

They responded asking for banking details which was provided. Once she received a partial refund, instead of it being R60 which would be the value of half the plant, they refunded R50 (which I am assuming is the R60 less the initial coupon code for the first purchase of R10). If that is the case then they took back the initial purchase coupon value as well. So she wrote to them to confirm.

She asked them how they got to R50 and their response was: The original price of the small mulberry was R199.99 sale price R119.99 You also received a iget10 discount, Price you paid R109.99, thus making your refund R50.00. Please note the product cannot include the shipping cost. You now paid R59.99 for the mulberry plant, plus your shipping cost. If you are not happy with the above I suggest you return the plant and we will refund you the R59.99, we will bare the return shipping costs.

(It is interesting to note here that they would be willing to pay the courier fee of R125 but make the R10 an issue. Also, to be technical, based on their calculation - which is incorrect - half would be R55 if they are working on R109.00, but you cannot calculate it like this).

My mom wrote to them stating: The original price doesn't concern me. I bought the plant at R119.99. Half of it would be R60. R60 I must pay R60 you must bear. My R60 is less the iget10 discount because that is for me - so I pay R60 less the discount of R10 = R50 You must still bear R60 so the refund should be R60 not R50. Or are you taking back your initial iget10 discount? And I already told you I cannot return it as it has been gifted away.

She received no response from them even though she requested a response several times. So one can assume that they did take back their discount coupon.

I would have given them 2 stars because I actually did get a plant (even though it was half the size as advertised) but then I dropped the stars to 1 because they took back their initial discount coupon!