Huawei Canal Walk: one month, no repair, and false accusations

On the 9th of February I upgraded to a Huawei P30 lite device at Cellucity Cavendish. Unfortunately, during lockdown the device stopped working - the sim card wouldn't read, though the handset otherwise functioned. We tried replacing the sim card, but it still would not work. When we contacted Cellucity, they advised - given it is still well under warranty - we take it directly into Huawei. As lockdown lifted, my husband took the phone in to Huawei Canal Walk for repair on my behalf. He first went to the store on 2 June where he was told that it was a 'motherboard' issue, and that it could probably be replaced the same day. However, he chose to leave and collect the phone on 3 June. On collection he was told it had been tested with the shop's sim cards and was definitely working. However, when he got home I tried my new sim card in the phone and it still was not working (The sim card would still not register, though the rest of the device functioned. We were certain the sim card itself was not the problem as we had checked it in my husband's phone). My husband then returned the phone on 4 June with the same receiving ticket he had had on the first delivery (please find attached to the email). He was not provided with any additional documentation. They suggested in the store that they would again look at the motherboard. On 7 June we then got a quote suggesting repair would cost us over R2000 with no other explanation. My husband tried to call and, when no response was received, on 15 June sent an email asking for the store to call us back to try understand why this second repair would not fall under our warranty. When we still could not get a satisfactory answer, my husband went back to the store for a third time on 17 June. We were upset not just at the failures to follow up with us, but that we were now being threatened with charges after the store itself had failed in the first attempt to repair the phone (and also misled us by suggesting it had been tested). However, rather than immediately seeking to address our problem, the store staff member Jackie instead insisted the phone had not left the store since 2 June. In fact, not only did they refuse to 'believe' my husband, but said they would not deal with any other aspects of the complaint until they had the opportunity to review the security footage to determine whether or not he had been to the store on 4 June. As of 25 June I still have no functioning phone, and no answer as the store has failed yet again to follow up with us when requested to do so. Beside the very obvious point that we would in no way benefit from lying about having collected the phone the first time (as confirmed by husbands bank statements that can confirm he was in Canal Walk on 4 June), the store is using that as an excuse to delay on dealing with the immediate problem which is that I have an unusable Huawei device, through no fault of my own, and in spite of only purchasing it in February. In my entire life as a consumer, I have never been baldly and falsely accused of lying by a service provider, instead of that service provider dealing with my actual complaint. It is beyond comprehension. I can't even send my complaint through customer service, as it won't allow me sufficient space to enter my complaint. Appalling.