You're probably using the wrong Derivation Path... ElectronCash (like Electrum) defaults to using m/44'/0'/0' for BIP39 seeds (Most common derivation path for BIP39/Hardware wallets etc)... for MultiBit HD based BTC wallets you need to use a derivation Path of m/0'

Basically, follow this video, but instead of using Electrum, use ElectronCash https://www.youtube.com/watch?v=E-KcY6KUVnY