So, the website is fine - I would have expected it to have been good if it was set up by these guys.
I wouldn't say the niche is flooded, that's not a thing - You just have to fight for your corner.
I would look up a few free courses on FB ads, CPC and Instagram ads. Take a look at what you are actually trying to do with your adverts.
I.e are you just sharing some clothes to an untargeted audience. Expecting mothers / young mums would be lapping this up, they love buying clothes, especially for their little kids.
So review some of yours ads, start by running engagement adverts against a post (open Facebook and type 'orders yours here' and see what type of adverts you get) . After you have run this for a few days, see what type of engagement you get and who is engaging the most (age, demographic etc). Once you have an understanding and some social proof on the website, look at doing some ATC (add to cart) adverts again starting low $3-$10 a day. Once you have seen a consistent add to cart (I mean 10+ a day) look at the data and then hone down your next advert for a purchase. if you get purchases and the cost per purchase is good, duplicate the advert with a slightly higher $$ per day amount.
Voila.