association used to sponsor welfare plan - who is responsible for missed 5500s

[TPApril]

Association was sponsoring a large welfare plan (medical), or seemed to be sponsoring the plan, for multiple members, but only one member group had over 100 ees. No 5500 filed for 2010 and 2011. Since 2012, members now contract directly with medical insurance co. - Who ultimately bears responsibility for the two missed years? Association may be interested in filing missed 2 years but they are not interested in paying the $4000 penalty, even though they understand the potential penalties.