Over the years we have received many low value small packets from UK eBay sellers via Correos.  Recently we have had two opened by customs and then sealed up with Agencia Tributatria Aduanas tape and forwarded to us.

Has anyone else had their post inspected recently?

I am still trying to understand the Canary ways, and I must admit—it is harder than I expected. 

One thing: I am buying from Amazon Prime - EU vendors etc. 
I am often asked for the paperwork, and my parcels stay for a month in Gran Canary. 
Sometimes, they ask for custom tax (again, for EU products coming from the EU), and I usually pay a bit more than 25% of their value. 

Is this legal? I understand there is a small VAT here (7%); it makes no sense why I need to pay so much tax.