A few notes about Jasminum Sambac and Maid of Orleans in particular

I had once a Jasminum Sambac 'Maid of Orleans', and to my experience, it is the less hardy of all Sambac cultivars. I had a cutting, and bloomed readily after rooting, indoor of course ! But to my guess, 'Maid of Orleans' needs a long period of regular heat, with a small thermal amplitude between day an night and a good hygrometry. Protect it from the winds, as they can cool down temperature very fast and 'hibernate' the plant, as colder temperatures are a great inhibitor to blooming.
A key to induce blooming with the species Jasminum - and particularly to Sambac is Long days, the longer day the better chance to bloom. So September, in our lattitudes may be the ending of blooming season for this species.
I would suggest to place it indoor, as you will have to anyway. Bear in mind that a cold night can kill this plant, as it happened to me. 10°C, and you can say goodbye to your baby Sambac...
Try to give it supplemental light / heat / hygrometry and it shall bloom.
Sometimes, a temperature falloff, especially any brutal change can stress the plant, and inhibit bud developpment, causing the bud to abort or look awkward, and that could be the case with you.
Remember that any plant from a serious nursery is given the best condition from day to day, to make a beautiful plant with a lot of flowers, as long as they want to sell healty and eye-catching plants. But when you bring you brand new baby home, the conditions - air - watering schedule - daytime/nightime temperatures - Light intensity, Light Duration - hygrometry - feeding schedule - may be very different and can stress the plant, especially if the change is dramatic, and sudden. This stress can inhibit bud growth.
Another guess if the plant is not blooming - 'Maid Of Orleans' might be resting. It might have set up a lot of flowers before you bought it, and then the plant is exhausted. Blooming is demanding a lot of energy, and as said in a previous follow up, this rest may be part of a natural cycle of this Marvelous plant. So be patient, another key to success !
Talking about desease, in my experience, Sambac are subject to spider mites attacks, specially indoor, and these pest can harm your plant, and cause bud abortion. Sometimes a virus (?) - Maybe agrobacter tumefaciens - can cause a kind of stem cancer. in this case, the stem, buds and leaves can be ill formed, and I can't tell if there is a solution to this... it happened to me though...
Sambac cuttings are really easy to root, with or without IBA (hormone) so you may want to take a few and try to give each differents conditions of light/heat/hygrometry, and with this kind-of method of trial you might find the best condition in your area for your Sambac, and get new clones for free! Mathematically, the more plants, the more blooms at one given time, the more fragrance in your room !
Maybe you'll get to the point when you can make 'Lei', fragrant necklace, a great gift to offer to your beloved... as they do in India, especially on wedding days...
Don't misspell ! This is "Maid of Orleans", NOT "Maid of New Orleans'. This is related to the french heroine 'Jeanne d'Arc' A.K.A. Maid of Orleans (Orleans, town from the North of France). The flower might have been given her name in symbolic reference to the white purity and the holly fragrance of the flower... Anyway I guess there are still some maids in New Orleans... So I won't bother if you insist