@Mainvijay unfortunately you never mentioned the username of your gold account before, so I tried to contact your other account for about a week. Please contact me ingame on Gold or on discord so we can arrange the trade
Rotom 300k sold.
To access the Pokemon Tower Underground you need an active Membership. You can buy a Membership Medallion on the Coin Shop or from other players for example.
Random PvP wins do not give you a PvP Coin. If you have gotten Coins from that, it was because of a short timeframe where it was bugged and rewarded PvP Coins for a win.
However you get PvP Coins from Random Ranked at the season end: