Guys what should I say to get card RMA d ?

So guys my 1660 super been acting crazy , it's not staying inside the OC and I have tried all kinds of OC , it stays in it for an hour and reverts back to whatever it desires to pulling high temps , giving extremely bad hashrate and highest amount of electricity also , so obviously I think it needs repadding or reapplying of thermal paste or so , so as a last resort am thinking of getting it RMA d , but what will I say to the MSI service centre ( the card is a MSI VENTUS 1660 super ), i obviously can't say it's not staying within my OCs or giving enough hashrates for mining

So what should I tell them is the fault with the Card is

And yah once it slips out of the OC , when I try to put it back it's just crashes and freezes the system and a blue screen appears saying either video TLDR error if the display is connected to the GPU or if it's not it says watchdog error or time out something like that

So guys what should I say ?