Max volt no sim?

I changed my package on virgin to max volt to save money on my phone bill as it was explained to me that you got an o2 sim at no extra cost. No sim was received so I phoned customer services to query and was told only new customers can get this deal. I asked them to send me a sim as I am able to cancel my current o2 plan as my contract is up. My opening line when I originally contacted the was I wanted this package as it included a sim otherwise I would not have taken it out. It was my understanding that all max volt customers got a sim for o2 unlimited at no extra cost? Nobody seems to want to help so I am going to have to cancel as I just keep getting passed between virgin and o2. O2 are saying I need to pay £20 a month? Virgin are saying I don't get a sim deal with this package even though I found this :
perks
Max Volt comes bundled with an O2 Classic Plan SIM. This gives unlimited calls, texts, and data, plus roaming at no extra cost in 75 destinations.

Customers also get to choose one O2 Extra for three months, such as Disney+ or Amazon Music Unlimited. If you already have an O2 mobile plan, Volt benefits apply automatically: double data on your mobile and roaming upgrades. The customer service people are all saying different  things so think I am going to have to contact the ombudsman. Any ideas? Been with them for years and this is how they treat you. Looking elsewhere before my 14 days is up