https://www.gov.uk/vat-registration/registering-vat-other-eu-countries

Registering for VAT in other EU countries
Usually, you only need to register for VAT where you’re based.

But if you’re supplying digital services to consumers based in other EU countries, you must either:

register for VAT in each country where you’re supplying digital services
sign up for the VAT MOSS service
You need to do this even if your turnover is below the VAT registration threshold.

Digital services
Digital services include things like broadcasting, telecommunications services, video on demand, downloadable music, games, apps, software and ebooks.

 HMRC Fraud Hotline https://www.tax.service.gov.uk/shortforms/form/TEH_IRF?dept-name=TEH&sub-dep%20%20t-name=&location=39

Представитель ХФ пишет про правила ЕС , а почему тем резидентам  ЕС кто оплачивал картами вы присылаете фактуры без начисления НДС ( VAT ) ? Вы должны быть зарегистрированы как плательщик британского или эстонского НДС , ведь вы продаете услугу вычислений в ЕС резидентам ЕС .

это написано здесь https://www.gov.uk/vat-registration/registering-vat-other-eu-countries

Registering for VAT in other EU countries
Usually, you only need to register for VAT where you’re based.

But if you’re supplying digital services to consumers based in other EU countries, you must either:

register for VAT in each country where you’re supplying digital services
sign up for the VAT MOSS service
You need to do this even if your turnover is below the VAT registration threshold.

Digital services
Digital services include things like broadcasting, telecommunications services, video on demand, downloadable music, games, apps, software and ebooks.

а сообщить в Управление Её Величества по налогам  о нарушениях можно здесь HMRC Fraud Hotline https://www.tax.service.gov.uk/shortforms/form/TEH_IRF?dept-name=TEH&sub-dep%20%20t-name=&location=39