Ok, whatever you do, do not cancel from your end otherwise you will get penalised.
The guest contacted you via text on you mobile - I suggest you respond to the guest imediately via Airbnb mail stating the you have received their text message requesting to cancel and that you would prefer to correspond via the Airbnb platform because any communication via text messages, WhatsApp, personal e-mail etc. is not acceptable evidence of communication to Airbnb.
Reiterate what they have confirmed that they wish to cancel but were unable to do so on the Airbnb platform. Ask them what particular issue they faced in attempting to cancel. Inform them to contact Airbnb to resolve this as you as host cannot cancel the reservation otherwise you will get penalties from Airbnb including blocking those dates these guest requested in your calendar so nobody else can book them and a possibly fine.
Also remind them of your strict cancellation policy which means that they will not get a full refund. All this has to be documented on Airbnb platform. Inform them that they need to do this ASAP otherwise their reservation will become active tomorrow which will have an impact on the amount of refund they receive. But please, DON’T fall for cancelling it yourself!
All the best,
Ama
PS, options for them to contact Airbnb - Contact Airbnb
Penalties for hosts cancelling reservation - https://www.airbnb.co.uk/help/article/990/how-do-host-cancellation-penalties-work
