WCA telephone call

Supposed to have a WCA telephone call between 1 and 4pm , no call came , I called the helpline and they tried calling the people who were meant to call me and said the lines were busy and that they’ll email them to get them to call me , no call came , nearly 7pm and I receive a text saying a voicemail was left by the people who were meant to call asking why I failed to attend my appointment even though my call log shows no incoming calls and my signal is fine, I checked with my network provider and that was fine on their end , I had used my home phone to check to see if i received calls and that worked  , I think they just bypassed and went straight to voicemail to avoid talking to me , what should I do ?