Ferns N Petals — placed an order and is still not delivered (kept the item on hold in their location)

I ordered an item for my sister in silchar and the delivery date was 25th sep for her birthday (Which was on 22nd sep). And requested for expedite the process as she will be gone on 26th sep night.
The item did not reach her yet and its 27th sep already. The status i get is the deliver personnel needs a landmark of a small town. My sister informed them a landmark (Assam university, which i suppose anyone in silchar will know) on 24th sep but still it is not delivered.
If landmark is so important then why is it not mandatory field in address section of ferns and petals. Why is it optional?

I informed fern and petals customer care that she will not be available so get it delivered on time. They said it depends on courier service and closed the incident/ticket i raised as they are holding the item in their location and not delivered (As per status). Neither did they try to contact my sister on 25ht or 26th for delivery. No solution of their delivery process and nothing on full refund as well.
And in fern and petals they mention on on-time delivery.

As its a plant i ordered and no one is their to collect, they neither refunded me the amount and nor the item has been delivered. Just kept it with them.

I am so disappointed with the customer service of ferns and petals as they do not give any solution, just that we cannot do anything. Is this the service they should provide to customers?
After complaining them multiple times since 24th sep, they stopped responding and acting on the complaint i raised.