Still awaiting a refund for our flights that were ...

Still awaiting a refund for our flights that were cancelled on 22nd March. We've had very little information or contact, always us chasing them instead of them being proactive. We were told on 23rd March our refund would take 6-8 weeks and we heard nothing from them until 5th June when they only offered a partial refund and we still haven't received even that despite being told it would take 10 working days. Will never use this company again.