kitten is scared....after a month

[Lala]

Hi there, I think I really need help and advice from people who have good Bengal experience and general kitten development knowledge. This is going to be a bit of a sad post, as my heart is literally breaking at the decision I have to make, and it is a very, very hard one. I need to decide if I should keep the kitten I adopted about a month ago or give it back to the breeder.
The kitten is adorable – very cute, sweet and kind. The problem is that he is not adjusting well in the household. When we brought him home he hid under the bed for about a week, then started to come out slowly. We (me and my husband) never ran after him, scared him or made him uncomfy. We play with him every day, each about 30 min and he loves it and purrs. He eats well and uses litterbox.
He is about 4.5 months now, and literally scared of everything. He would not let us pick him up, or approach him – he runs under the bed immediately. The only time I can touch him is when he is in his cat house – then he purrs and seems to love petting and attention. He never goes out of his safe room, even thought it has been a month we had him. If he does, then only for a few min and runs back under the bed – and we live in a 3 room apartment, so the place is small and not intimidating at all, there are no other cats/animals around. He sleeps most of the day and will come out only if attracted with the toy – he never comes to us unless to play or eat. He hissed at me for 3 wks when I was giving him food, but stopped this week. In general, he never jumps anywhere and prefers to be on the floor so that he can run away if he needs to. I am patient, but my husband is starting to get irritated, because it is stressful for him to feel that all he does scares the cat. He never jumps on bed or comes to sleep near us, even though we play with him in bed…. I called the breeder and asked for her advice, she told me that she suggests we don’t talk in front of him, address him only with the toy and walk without slippers. She told me that if this continues and we are not comfortable, she will take the kitten back and will provide me with the refund. She also told me that she is sure he will outgrow this and by 1.5 year he will be with us all the time – that he is a kitten and this is a normal development. I had 3 cats before, even a feral one, and based on my experience with regular domestic cats, this is not a normal development at 4.5 months, and a month in a safe and loving environment.
I am not sure how to proceed. I am attached to this kitten, obviously and want to keep him, but I am also honest with myself as of why I purchased a Bengal. A friend of mine has one, and he is very active, engaged with people, not a lap cat but a family pet. And I was very opened to the breeder about the personality of the kitten that I want. Many of Bengal loves could be very upset at me, for not wanting to work with the cat and not accepting him for who he is. I am working with him – all the time, but I see very, very little progress and I am afraid that I will end up with anti-social cat that does not like people – which is totally opposite of what I wanted when I was getting a cat.
If possible, I would like to hear feedback or opinions on his development and is it possible for him to turn out more friendly as the time goes? May be someone had a similar situation? Anything that can be done to make him less scared?
Thanks!