UNPROFESSIONAL AND BAD TREATMENT BY GMI GROUP

I went to Sky City looking for a space/shop to rent. Fortunately shop No 22 was vacant, Andri Lotz asked for the pictures of what i will be selling, I sent the photos, she then asked for my business plan, I sent it. She sent me a form to complete and requested for a number of documents such as ID copy, bank statements, proof of address etc, All that was sent. She sent me an offer and asked me to sign and return it as soon as possible, I did exactly that. They then told me that I need to submit the shop lay out, signage design and pay the deposit, they sent me the quotation and a letter confirming their bank details, also,the email stating that I need to pay before the 1st of May. I submitted the shop lay out and paid the deposit. Around the 3rd or 4th of May, Andri Lotz sent me an email saying that i need to also submit the design of the signage before i can be given the keys. I submitted the signage design on Friday, the 7th of May 2021. On Monday (10 May 2021) I called Tania who is the tenant coordinator and asked her if she was happy with the design as I was told that she is the one who approves signage designs. Tania said she's happy, the signage is beautiful she said she will call Andri and ask her to tell me when can I move in. Around 13H30 on Monday I decided to call Andri to check if Tania had spoken to her. To my surprise, Andri told me that the email that was sent to me was for the cancellation of the offer. I asked for the reasons, she said the landlord thinks that I will not be able to pay rent. I tried to ask her questions such as- why are they saying that only after so much effort, time and money wasted, what makes him think I will not be able to pay, where was the landlord all this time...she refused to answer all those questions saying she was just a messenger. I feel that I was not treated fairly by GMI properties, they wasted my time, money and energy. They also raised my hopes for nothing. If they needed the landlord's approval, why did they make me to go through all this?