PCR Test didnt show up, what do I do?

[FrodoAteMyRing]

Hello all posting here for traffic as I dont know what to do and google seems unclear, at least to me.
Im back from abroad, today is day 2 and my booked pcr test hasnt shown up yet. I checked the tracking no with Royal Mail and they claim it has been delivered, it has not. I even looked behind and in the bin and asked my neighbours. I just send an email to the test company as Royal Mail shirks all responsibility and says to contact the sender.

My question is what do I do? Is it ok to just self isolate for 10 days? Or?

www.gov.uk/government/publications/minimum-standards-for-private-sector-providers-of-covid-19-testing/day-2-lateral-flow-tests-for-international-arrivals-minimum-standards-for-providers

Where a test kit is broken, is not delivered or gives an inconclusive or invalid test result, the provider should offer a replacement kit as soon as possible to the consumer.

The Covid board gets a lot of traffic too.