Contact aproved . No stock so sales lady want to cancel deal

I app**** online for device huawei mate 20 pro on 29 July lady called back within 10 min did application it was approved said money will be debited in 48 hrs . Thursday 1st lula morning I called telcom saying they never debited my account .. 2nd August telcom debits 1st instalment to make sure it's ryt account ..3rd August I received a sms the device I've ordered is out of stock once stock arives order will be issued. ...4th of August sales lady called says phone I ordered has reached its shelf life telkom will no longer be keeping device I must take a hawae mate 20 lite I said I wanted hawaii mate 20 pro so if they can't get it then I don't want another phone . But if tye lady checked stock with me on phn and the contract was approved . Shouldn't telkom keep to there contact .if I absconded from contact and don't pay I would b blacklisted but if telkom does it fine it's very unfair ..... I got a sms saying .Your query will be attended to.Your case number is ***4 if I go on telkom site put in no. It says cancel product I'm really unhappy with telkom I want my device ..... not deal canceld