Spouse Visa

[ZAK86]

Hi All. New to this forum.
Just wanted to ask any idea about my case.
I got ILR in march 2017
Applied for my wife for spouse visa end of March we gave been married for 5 years but I was previoulsy dependent on her Visa.
On 23rd of May we received letter from HO asking for proof of address for both of us for the last 4 years almost.
We have sent more than 50 letters addressed to both of us in that time frame.
It's been over 3 weeks now we didn't hear any thing back from Ho.
Anyone went through same kindly share or any advice wether to ring HO for an update or wait.
Thanks .