Its possible some wires got crossed behind scenes, some database/software mixup.
Maybe email proton support if you’re concerned? I’ve had some similar mixup happen with banking and they got it all sorted after I complained (I was getting emails intended for someone else).
Edit: either way, I think you should let them know in case its phishing or something broken on their end.
Kept a hand knit wool scarf (they made for me) for around a decade. Outgrew the style but it was a damn good scarf.