Help can not get my NEM mainnet on my android phone to work

Hi,
l will be in Brisbane in early July and looking for someone to explain how to use the Nem Mainwallet.l use bitcoin and dash all the time but when using the Nem mainwallet it was okay putting Xem on it; however when l have to withdraw Xem, no luck when l scan QR code for Xem on one of the exchanges it reads "invalid Qr code"l am still a big fan of this currency as it has great functionality but for me being tech compromised no luck.Looking for a kind techy to help me out reward free coffee some Xem and the everlasting gratitude of a non techy.
Cheers Trev
Ps l use Bitcoin,Dash and potcoin all the time but l think the systems are very different ???