The WestJet website really is a frustrating mess ... especially when it comes to viewing or managing any booked flights (and doing seat selection). I also enjoy the endless loops I sometimes get stuck in, where I’m asked to log in three separate times during one single session on their website.
I had the same issue as the OP just yesterday.
Booked a flight online via our corporate travel agent. Afterwards, went to the WS website ... where my itinerary showed up — with the “Select seats” button active and highlighted for that itinerary. (Everything else was greyed out). I clicked it, and the page advanced to a new one that showed “Step 1 out of 3” at the top. But there was nothing else on the page. No seat map, no navigation, nothing. Just a whole lotta white.
I assumed it was my Chrome browser, so I tried IE. Same dead end. More wasted time.
Then, I tried the WestJet app. “Seats” button was similarly highlighted, but - again - navigating through takes me to a blank page. Grrrrrrr, WestJet. This is frustrating.
Then, I called in once I got home It was a 25 minute wait, staring at a wall in my house ... all so I could hand WestJet my money. Because their web-site doesn’t function.
Per the agent gent on the phone, it never works, and he always gets a lot of people calling in with the same problem.
Come on, guys. Fix this.
—— Edited to add: Oh, and they couldn’t give me a receipt for the seat selection fee (a work expense). Because their system can’t handle that. So the agent had to take an extra few minutes, with me on the phone, filling out some special receipt request form that would have to go to a different department. Wow.