It's relatively common IME if you have a hard question or unusual request. Presumably it's going to affect the support person's metrics so they 'accidentally' drop you. Or, if there are targets then it might even be policy.

I've been on calls where it was 30 minute waiting to get answered, you ask for what you need, they put you on hold (or 'transfer' you), then the call drops. They don't ring back.

Telecoms companies in UK seem to have the worst communications, terrible line quality on support calls. I just assume people then don't complain because it's so hard to. The ombudsman is next to useless - you have to be without service for something like 6 weeks before they'll get out of bed.