Shocking bad customer service

They might think they are one of the greats but quite frankly their non-existent customer service is beyond a joke. I have been trying since the beginning of March to upgrade my contract. My 2 phone calls in March were obviously a waste of my time as nothing was done on my account. Phoned again at the beginning of June to resolve - lots of promises and incorrect info. Phoned again at the beginning of July - again incorrect info given. They owe me a refund which they refuse to give me - wanted this escalated. Got a couple of SMS's saying that I would be contacted with the progress yet 9 hours later another SMS to say query had been closed and that they hoped I had enjoyed my customer service experience!!!! If getting no service is meant to be enjoyable then I suppose yes I did enjoy it!!!!! Tried phoning again but couldn't get through so got a human to phone me via the Tobi app. However was told no refund - requested a supervisor to contact me - still waiting a day later. Wish I had cancelled my contract and gone on prepaid - will be doing so once this contract ends. I know we are in the middle of lockdown and they have less consultants but no excuse for the lack of follow through from promises made via SMS.