Did this ever happened before an brown garter giving live birth to eight teen ring neck snakes cause it happened to mine which got pregnant in the wild and had babies in captivity?

They were other garter snakes. It is impossible for a garter snake to give birth to a ring neck snake. They are very different snakes. Garters are semi aquatic ovoviviparous colubrids while ring neck snakes are oviparous rear fanged snakes that are venomous to other reptiles along with amphibians. You said you got it in the wild? Let it go. You want a garter snake - go to a reptile shop.