Signed up for Avis Preferred weeks ago (J1R503), but Avis Website online states my "Card is used by another Account" - Avis Representatives & Customer Services CANNOT assist

Being a regular Avis car rental patron I signed up to Avis Preferred program to enable easy collection of vehicles i.e. having a profile with Avis would save the need to complete all my details and payments online at each booking and also forgo the requirement to queue and fill in forms at the Avis collection depot. I received this lovely message at the time of my signing up :- "(Congratulations, you've just unlocked a world of benefits with Avis Preferred. Your new unique customer number is J1R503. When booking online, be sure to sign in so your rentals count towards your loyalty balance." but since then and including immediately afterwards attempting my first booking, absolutely NOTHING has changed i.e. neither my name nor my email address and even my preferred number is recognised by the Avis website sign in attempts - These are AVIS responses: "Sorry, we could not find your customer ID. Please provide valid ID." "It looks like your card is already registered to another account. Please log in using those details." "Sorry, that user account doesn't exist. Please try again or call ***/ +2 ********** ." Not to mention all the supposed benefits I was to have received signing up as a Avis Preferred member with so many rentals (7) having taken place already over the last month!!. Not a single member of Avis customer attendants has been able to sort out the problem - only can attend to their one single rental! Customer services has yet to reply/respond, however I did receive an email 2 weeks later asking if Customer services had sorted out my query, to which I rep**** 'NO, no response yet' and a month later I still await assistance. SHAME ON YOU AVIS! Your website is very much a user UNFRIENDLY site for any problems other than RENTING/BOOKING a vehicle.