Q.Curry leaf plant
I live in Spain and I bought a curry leaf plant on Amazon from England of about 10 inches tall on December 12th and it has grown two leaves (branches) on the top, but in February there was like a kind of tiny shoot on the apex of the plant but then it fell off. Now March, I saw a yellowish leaf at the end of one branch and it fell (I used a lens to check it and it looked a bit brownish with white dots, though not too sure).
Am sending you three photos, two of the plant itself and of the dead leaf.
As to Insecticide and fertilizers, am also sending you what I bought and just want your advice if buying the correct ones and how often should I use them, especially now in spring towards summer.
INSECTICIDES – Which of these is best and when/how to use?
1) Bayer Advanced NATRIA 706250 Ready-to-Use Neem Oil Pest Control, 24-Ounce Bayer Advanced
2) Bonide 022 Ready-to-Use Neem Oil, 32-Ounce
FERTILIZER
I am using for fertilizing (Miracle-Gro 1001502 All Purpose Liquid Plant Food Concentrate, 32-Ounce (Plant Fertilizer)
Please do help me. This is my third curry plant. In Spain we have good winter and sunshine even in winter and have the plant indoors since December.
Thank you 🙂

Your plant may have Scales or Mites.
Neem Oil is good treatment for insects or fungus issues.
It is organic and safe for people, pets and bees.
A fertilizer recommendation for a Curry plant is a Seaweed or Fish Emulsion fertilizer.
Here are some links that will help you with care requirements.
https://www.gardeningknowhow.com/edible/herbs/curry/growing-curry-leaf.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-kelp-fertilizer.htm