I dont know the excact answer, this is a guess.
In the computer shops online they write they expect the ryzen cpus in stock in april month.
However personaly i think they will first be avaliable in summer time since allot of people have ordered some hardware and dident get it yet.. Nobody knows when the cpus or gpu's will be avaliable since there is a lack of computer ships in the entire world since they are producting 5G network things, electric cars and computer/mobile phones and so on on a very high level.. no supply is normal right now.
Regarding rma if things where optimal.. well expect 7-10 days before your cpu arrive at the shop.
If its a big shop they might be able to diagnose the cpu fast, so after arrival maybe 10 days later.
THen you properbly will get a note asking what to do.
Do you want money back ?
or you want to wait for the cpu to be replaced then you should expect to wait x month.
My personal guess is dont expect a new cpu for the next 3 month, ask for a refund and buy a used cpu so you can use your computer and then buy a new cpu when it become avaliable and sell your used cpu.
