Overcharged for a service I'm not receiving - Poor service

I've been paying for 20/10Mbps since September 2021 and have only had 10/5Mbps speeds since. I've opened multiple queries and have spoken to numerous Mweb agents since Sep-21. We've tested line speeds multiple times and even had a subcontractor come out to my residence to test the speed. There is no fault or issue on my end as confirmed multiple times by Mweb and the sub-contractors. I keep on raising queries with Mweb but receive no feedback or actions to get this problem sorted out. I've insisted multiple times that I want to escalate this to management and would like to be refunded for my over payment. This is extremely poor service from Mweb.