Thanks so much for the replies.

I used fine sand as substrate ( by exoterra ).
Temps cool side 80F, warm side 92F and room temp at night which is around 77-80F.
A photoperiod of about 12hrs on and 12hrs off was provided and I used
"Sun Light" by exoterra.
Humidity was between 50-55%.
His staple diet was appropriately sized calcium dusted crickets and greens.
But he was fed almost exclusively on mealworms on the first few days I got him, could that have been a factor?

He had seizures when he was 4 months and that was when I took him to the vet. He was actually boarded out at the vet for 2 months, and his spine and tail were already malformed by then. The vet told me that it was due to lack of calcium at the early stages but he was fed on calcium dusted crickets, so I was really puzzled. I was advised by the vet to add vitamin E supplements.

I could not identify any one particular area where I went wrong, but I guess the substrate may have had an impact and so too the mealworms.
But most beardies are kept on sand substrate and do just fine,
that`s why I`m just full of ????