Recurring issue on Samsung A50

This morning I took my Samsung A50 in for a second warranty assessment within a couple of months from receiving an upgrade. The recurring issue with this phone is when placed on charge, it goes completely dead & further functionality ceases to exist. I am really concerned about this model of phone & when expressing my concerns to the assistant manager at the MTN Store - Canal Walk Centre, Century Place Boulevard, Shop 101, Canal Walk Centre, Cape Town, I receive no comfort of a replacement being void of this problem. Surely, the store would need to look into this batch received & why it is frequently brought back with issues. Could it have been a faulty batch perhaps? In which case, the batch needs to pulled from shelves & returned to supplier. Also, when asked if I could rather take a different phone of same value, I'm told not & would only be considered after a fourth warranty assessment. This I find unacceptable because what if that warranty assessment happened to be outside the 6 month replacement warranty? I would no longer be able to exercise this option & be stuck with a phone needing to constantly be taken in for repairs. Please advise, as I would not want to receive another Samsung A50 on replacement & would rather want to opt for another phone of same value, I would be confident of not having to return with same issue.