Complaint zando don't stick to turn around time

Ive downloaded my zando app as they are currently running a major sale and I want to complete my purchase I'm struggling to use my first time user voucher but I'm unable to I've been trying to contact them since Saturday they have a three hour turn around time it's been more then 48 hours. I understand with lockdown etc but hence virtual offices and they opened up their "doors" again so they had to be prepared for queries, complaints etc I just need someone to contact me ASAP.