My banking profile blocked while having dinner and was unable to pay my bill.

I had a worse traumatizing experience of my life. I took my kids out for dinner at Spur, while eating I went to my Tyme bank App and did 2 transfers of R5k and R500. Then few minutes after, I received a sms that says "We detected a suspicious activity on your account and it has been blocked" I then called the number that the sms came with to contact and for good 30min I never went threw, I would hang up until I run out of airtym. The bill came and I had to make payment, the card DECLINED. It was like we went there to eat fancy without money and we had to do uncomfortable things and leave some of my belongings like my watch to assure them that i will come back to pay. How can Tyme Bank block someone' account instead of calling the customer should there be some suspicions of some sorts? I am not sure anymore after this incident if i would like to continue with Tyme Bank.