Try calling this supplier via a Phone Call ...
Sometimes suppliers are very busy running their day-to-day business and are not always online to read and/or reply to PM's.
I doubt this supplier is deliberately avoiding you ....
I suspect there will be a honest and unintentional reason or circumstance that has lead to your loss of communication.
There simply wouldn't be enough Financial Monetary gain in your purchase for any Reputable Supplier to Discredit himself on a public forum via an Un-Honoured Sale.
As I mentioned .... try a Phone Call ....

.... & be Explanatory, Composed & Polite.
With reference to Admin .... the most appropriate person to seek advice and/or intervention from is this clubs Liaison Officer: Shane aka
LZY_EYE
Hope you Resolve your Issue Soon.
Sam .....
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control