It's true- in the UK, you vote for a person to be an MP to represent that constituency.
That person can then do whatsoever suits themselves as 'representation' until the next election.
They are not bound to any promises made, or to represent any particular views or any party.
You may have thought you could vote for a right or left wing party, or leave or remain but your MP can can do as they please once elected, including defecting to the Monster Raving Loony Hippey Yoga Party or casting votes in parliament that clearly do not reflect the views of the public that elected them. That's what we call democracy.
As to the 3 years of dither and delay, well, that's not over either, there's at least another year of being bound to the EU and all it's regulations to go yet, if not far, far longer.
To shorten the agony of the now inevitable, they might consider actually getting on with it. Ergo.
Cancel HS2 and use the money to restore Hadrians |Wall so that Scotland can have it's Inde-Ref ASAP.
Re-instate the Irish Border immediately, we're not in the bloody Schengen-Zone.
And for what rational reason are authorities 'rescuing' migrants out of the channel ? Sure, if they make it to dry land, by all means round them up and throw them in one of the concentration camps provided therefor. But if you're going to pick them up the moment they paddle into the North Sea, then just lay on some ferries and be done with it. The whole point of having a large stretch of water as a border is that it is difficult to cross. Countries don't have river and sea borders by accident.
Not suggesting that any of the above is morally righteous or even what people voted for, but it would bring a swift end to all the dithering, the years of wrangling, the floods of migrants and the end result of Brexit in name only with all of the drawbacks, rules and regulations still imposed but none of the benefits or any say in drafting them.