During December, the RMT called strike action which massively impacted passengers. 
Whatever the rights and wrongs of this strike, passengers were still charged a full fare when travelling in spite of the fact that the service was seriously reduced. 
SWR are only offering delay repay based on the amended timetable. 
To use my journey as an example:  I was having to get up at 4am to make sure I could actually board one of the few trains to get to work on time.  This was after using a replacement bus service.  My journey time increased by an average of two hours per day.  I was not alone in this, in fact I was one of the lucky ones, given that some stations were not served at all for the duration of the strike.
SWR should be compensating season ticket holders for the disruption and not be charging a full fare on day tickets.   This is an opportunity for the new MD, Mark Hopwood to actually put passengers first.