Offered me one thing, then provided something else - Misleading

In summary, I was offered an incentive package by the Vodacom Cancellations Department. The package offered by the call centre representative, and which I had agreed to, is a U-choose Flexi 125 which consists of R125 airtime and 2,5 gigabytes of data for R69 for a period of 24 months. The contract was upgraded on 12 April 2021 and commenced on 01 May 2021. However, till today, I have not received the 2,5 gigabytes which were agreed on but instead received only 500 megabytes. I have followed up with Vodacom a number of times, however, this has yielded no results, except for excuses and empty promises to return my call to address/update on the issue. I expect Vodacom to stick to the telephonic contractual agreement, and correct this discrepancy, whilst compensating me for the days where I did not receive access to my full allocation of data as per the agreement.

Below is a chronological timeline of events for reference:

2021/04/21 | 13h45: I received and accepted an offer from the Vodacom Cancellations Department to migrate to the uChoose Flexi 125 package with R125 airtime and 2,5 gigabytes of data for R69 per month for 24 months.

2021/04/30 | 07h04: Received SMS to notify that my migration to the uChoose Flexi 125 was successfully completed.

2021/05/01: My uChoose Flexi 125 contract commenced.

2021/05/07 | 10h37: Received Vodacom invoice via email where I first noticed the discrepancy whereby I am not receiving my full data allocation of 2,5 gigabytes, but instead have been given 500 megabytes of data.

2021/05/07 | 12h56: Called Vodacom. Spoke to Asanda Ndlovu in the Cancellations Department. She advised that the package that I was offered is only available to customers whose numbers are on the old system, that I was incorrectly offered this package. I told her that I will not carry the responsibility for any errors on Vodacom's part (as there was recorded verbal confirmation of the contract details prior to the contract being processed). Vodacom must supply me with the correct allocations for the period of the contract as agreed. (Secondly, it makes no sense to me that the longest-standing Vodacom Contract Customers, who have been brand loyal are the ones who are always being at a disadvantaged by a disfunctional dual system. All the numbers should be migrated to the current system.) She responded that she will get the consultant who facilitated the migration to call me back to rectify this. I received no such call.

2021/05/07 | 14h03: Sent an email to Vodacom Customer Care regarding my issue. I received an automated authentication response, to which I completed and rep****, but received no response since.

2021/05/17 | 15h20: Called Vodacom again. Spoke to Mohammed in the Cancellations Department. I insisted to speak to the Manager, however Mohammed initial resisted, recommending to divert me to their ***** department. I insisted to talk to the manager, as I believe this an internal departmental discrepancy.

2021/05/17 | 15h20: I was transferred by Mohammed, and spoke to his manager Chris. Chris reassured me that I will get the agreed data allocations, and that he will send an email to the back office to have the discrepancy resolved, and that I will receive the balance of the data before the end of the month. I was advised that I will receive feedback within 24-48 hours with regards to communication with the back office, as well as a call with an update before the end of the day. However, till this day, I have not received any call, feedback or balance of my data.