Bound matter of electron and positron has already been observed and the existence of such particles is generally accepted. Most simple particles are positronium (1 electron + 1 positron), and the di-positronium. (2 electrons + 2 positrons). These have been created by collision experiments with positrons. Both particles are instable. The decay reaction is an apparent annihilation to energy which is released by gamma rays.
See separate page for "Annihilation".
In VTOE the observed annihilation is no real annihilation, but just a rearrangement of the fundamental particles from the centered form to the non-centered form: the positronium transforms to an electron-neutrino and the dipositronium to a muon-neutrino. The released energy is conform to this reaction as the mass of neutrinos is zero or nearly zero
The neutrinos are difficult to detect and therefore have not been observed. This led to the assumption that the reaction is an annihilation of matter..
The rearrangement of the positronium to an electron-neutrino is possible when the spins of electron and positron are different, that means for the para-positronium. The ortho-positronium has to react with dark matter before transformation to neutrinos. So the ortho-positronium is more stable than the para-positronium.