Triploids of many crops are usually seedless ( watermelons, Citrus, banana ).
In that case what is the normal seed count for the fruit of the types you are trying to cross ?
If it normally sets seeds, probably not a triploid ??
Another possibility is different chromosome numbers in the parents you want to cross.
What are the chromosome numbers of the species/varieties you want to cross,
or the chromosome numbers of the original parents of the "Painter' ?
Is Painter itself an unusual or wide cross ?
A quick search said that "Chromosome numbers of Annona are 2n = 14 and 2n = 16, except for A. glabra, which is a tetraploid species (2n = 4x = 28).
That would then be 1n = 7 X 1n= 8 for some crosses, which may never or rarely work.
Have you tried using Painter own pollen to achieve fruit set, to test your technique ?
If you can easily recognise hybrids among the seedlings, mixing pollen may get fruit set and hybridisation.
Mixing pollen is often used to overcome incompatibility in wide crosses in plant breeding.