Membership Application at DHMS

Trying to sign up a new membership. Have been advised that due to being out of the country in the period 2005 - 2009 and not being on a South African medical aid, my husband and I have to pay a penalty. Have been on DHMS since returning in 2010. Further, our medical history reflects low risk- no chronic conditions, no abuse of the scheme during our membership. Does Discovery have too many members, should we look at another scheme? Very disappointing