No! And Hello old friend!
That is ridiculous. She thinks because she buys a fair amount that she can just hoard things til she decides? Nowhere on earth in a b&m would that ever happen! That would be like going into a clothing store where there's only one of each item, grabbing an armfull, and asking the clerk to hold them for a month. You would be lucky to get 24 hours.
I only reserve for 24-48 hours, you less prior arrangements are made (they don't get paid til next week), but have never extended it beyond 10 days at MOST, and that was because they were very sweet :-(. Don't question yourself. You did nothing wrong.
And buying a lot doesn't automatically make a good customer, if they're tying up inventory that other potential buyers, especially those just finding your shop, would buy, but cannot. Sometimes the hassle makes it not worth it.