I asked mFortune why the wagering requirement showing on my account was 400x my bonus when the bonus was only 20x:
"Every bonus you receive has a 20 x wagering requirement, that is applied to the outstanding bonus wagering amount on your account. If you do not meet your bonus wagering requirements but continue to receive bonuses, the bonus wagering requirements do not automatically reset to £0 and will continue to increase. You'd need to contact us directly, when you have either £0 or £0.01 bonus credit on your account, so we're able to then manually re-set your bonus wagering requirements back to £0 for you."
"Every bonus you receive has a 20 x wagering requirement, that is applied to the outstanding bonus wagering amount on your account. If you do not meet your bonus wagering requirements but continue to receive bonuses, the bonus wagering requirements do not automatically reset to £0 and will continue to increase. You'd need to contact us directly, when you have either £0 or £0.01 bonus credit on your account, so we're able to then manually re-set your bonus wagering requirements back to £0 for you."