OTP's not working and requesting one is pointless

I constantly have issues receiving OTP's for purchases. I always received the OTP via SMS for more than a year and then all of a sudden a month or two ago it just stopped working. I am now required to reach out to a customer service consultant each time I want to make a purchase. They're only available from 8AM - 15:45 Mon to Fri to assist so I am unable to make purchases over weekends.

On 12 August I had to phone in to request a OTP which I received too late so I had to request another one via WhatsApp. Both agents were very helpful though.

Last night I wanted to make another purchase but needless to say I had to wait until 8AM today before I could make contact to request a OTP. Waited an hour and 20min before someone assisted me on their WhatsApp chat. Requested another OTP, only received it 40min later. Keep in mind a OTP is only valid for 15min. So I phoned again for another OTP and was told it would be sent to me shortly - it's now an hour later and only received it now. That means I need to contact a consultant again for yet another OTP which will probably also only reach me more than 15 minutes later.

After doing some online searching I saw that OTP's has been an issue since November 2020. Surely one would think it would have been resolved by now or that an alternative would have been implemented. Perhaps something like 2-factor auth using their app?

If there was another online credit provider with a 12 month repayment period I would have definitely used them instead of Mobicred.

Please fix your systems and infrastructure or provide an alternative method for your customers to receive an OTP. I don't want to contact the customer services team numerous times a day just to make one simple online purchase.