No explanation for why my data finishes quicker than before

In October 2020, I signed up for the 40gb+40gb for R199 sim only deal at Telkom in Sandton. They gave me 12gb for October because I signed up during the month. During October-December I used only 2 devices; my laptop and my cellphone. I use my cellphone for the internet and social networks, and my laptop for netflix, dstv now and youtube. The data that I signed up for used to last till around the 28th/29th day of the month and now it barely lasts for 15 days. In Jan, I ran out of data on the 13th and this month on the 14th. Now before all of this started happening, my devices were always connected, it would go as far as pausing whatever was playing without disconnecting, leave and go to the mall for hours, at times I would sleep with my laptop on (still connected) and my data would still finish at around the 28th/29th. When it happened the first time in Jan, I changed my lifestyle to make sure that it doesn't happen again. I metered the connection on my laptop, and whenever my devices were not in use, I would disconnect and my data still finished within 15 days! I went to the Telkom store in Northgate on the 15th Feb and I spoke to Martin. What was infuriating was that he was not willing to listen to my problem and every time I had something to say about the "possible cause" of my problem, he would change his statements and make other excuses. It started with "your devices just use too much data" to "is your software up to date?" to "your devices are malfunctioning that's why your data is getting chowed" to all other explanation that were not relevant to my issue. My only question is how is my data getting finished so quickly now (when the connection speed is not even that great) when I've been doing the same thing all these months? He couldn't answer this question. He called the manager and the same thing happened with him, he printed out pages of my usage stats and dismissively told me that my devices use too much data and that's it, they ignored the one question that I kept asking, I even switched to asking in vernac but they never answered. I then asked the manager to print out usage stats for Nov/Dec and he told me that I would have to call H/O and ask them to email me the stats he can't do that for me then he went back into the office and left me there hanging. At this point I felt helpless because the only people that I expected help from were gaslighting me and making me feel like I don't know what I'm talking about so I left. I hope I get help, I've seen many other people complaining about this on Twitter. What's the use of paying for a contract and still buy data during the month?...that's ridiculous!