From Vodacom to MTN...it's just a number transfer...

I just received my new MTN contract phone yesterday(26 February 2021), I am a first time MTN user, I am actually moving away from Vodacom because of their lack of signal coverage. I was firstly informed by a sales agent - Devon - that my internet request for contract of R279 for the Huawei P40 Lite cannot be utilized because the "codes" does not work, so he gave me a contract of ±R400p/m. Then why have it available on the website??? Second of all, he told me after I have asked him if it is possible to move my Vodacom number to MTN, he said it was possible, but I had to do it at my nearest MTN branch. I just came from my nearest MTN branch (27.02.2021) (President Hyper, Krugersdorp - would recommend them anytime), where they were very helpful, and they have also informed me that my number has been activated so there is no possible way of changing it, and even if it is still possible, they don't have the power (so to say) to do it, Only if I have opened the contract with them it would have been possible, because then they have all my information. So after almost 20years of using the same number and everybody has got this number, I have to change it because I don't have any other option.... I would just like an answer if it is still possible.