Well, if you asked for blackout lining and interlining that is what you should have got. Bonded blackout lining is not the same thing; it is just a thicker lining and will not give the same effect as 2 separate linings (which will be thicker).
I have just had some curtains made and would like some opinions. I paid for curtains with blackout lining and an interlining, the interlining being extra. They have been hung and are ok, nothing special. Having looked at them I can just see a blackout lining. I expected two linings - I paid an extra £80 for the interlining, the quote being in 2 parts, one for blackout and one for blackout and interlining. Any expert curtain people have any advice? Should I expect 2 linings? I know you can get bonded interlining but that was not what I was expecting. I did email the company who are local and well known.