Not always my experience.
We’ve got Virgin media for phone, broadband and tv for 66.50a month. I looked at what it would be to move up to 350Mbps, but felt 77 was a stretch too far.
Then got an email from Virgin to say cost was going up by 3.50 a month, so I went ahead and moved to the 350Mbps deal, 7 a month being OK.
I then got an email asking me to get in touch as part of the upgrade hadn’t gone through. To cut a long story short, they gave me the full package for 71, not 77, and threw in a free 40Gb SIM card with all calls and texts included, saving me 9 a month.
so all in all, very happy.