Tfg not addressing online technical issues with their system

Tfg online shopping is not possible for me I have been ordering online from Tfg via my iPhone for years however for the past 3 months most recent attempt today I cannot log into my online profile even when signing in as a guest the online shop does not process order on my account card I called Tfg about this previously it was not addressed as even now I am unable to order I called them again today and was told the problem is potentially my phone which I explained I have used to order online with Tfg throughout my account membership with Tfg they need to address thier system error blaming ordering from a mobile phone is unacceptable in this day and age it’s a iPhone for crying out loud and further more I did not have this issue prior to the past couple months