Faulty tablet

Good morning<br> I've upgraded one of my contracts over a year ago for a Huwawei 10.2\ tablet, in the first year, the tablet went back 4 times although I was informed after the 3rd time it would have been replaced. According to Cell C, it was replased, i informed the driver the tablet has not been replaced as there's a mark on the back which is still the same. This year, it went back for the same problem, firstly, i was informed it's out of guarantee and I need to pay for repairs, when I told them i refuse to pay as it's the same problem, afterwards i was informed the tablet not the one that's been issued and had different reference number, i told them, it's still the same tablet on which I was informed the casing remained the same only the inside parts were replaced, my question, why would they, after I was told I have to pay for repairs, then discover it's not the same tablet with different serial numbers? Why tell me the tablet was replaced, brand new, then afterwards inform me the casing the same but parts replaced? I think this is dishonest of Cell C trying to get out of repairing the handset knowing the last time of repairs it was NOT replaced."