How to counter spam Falls ?

I have played a game, and the OKW make 2 Jeep that I destroyed easily, and after he just spammed 4 sections of falls + 2 sturm + 1 puma, and i couldn't do absolutely nothing.

So how do you counter ? Guards ? Help me

If that's 1v1, here is my suggestion:
Agaist OKW start with two engies:while one squad is capping, another builds t1. Get m3 and one penal squad asap. If you confirm, that he can go for falls, just deny his puma arrival by capping cutoffs and as much standart points as you can get. It is important to have flamer, because t2 OKW will be forced into healing manually with crates since flamer have good aoe damage. This will deny muni upgrades to volks, sturmpios and volks.
Get t70 asap and then backtech to zis and maxim. Mortar can be a good idea too, if ylu need uncounterable recon.
Use t70 and m3 to bleed infantry, use zis barrages as much as you can, those are cheap and effective.
Guard motor is always a good doctrine pick, but also NKVD is great: you can get a commisar with propaganda to debuff/forceretreat blobs and anti-tank overwatch which is great against armor.
KV8 is good against puppchen spam also, but katy is more conservative valuable pick.
If you play against falls, it is important to get AA after your medium armor reaches the field.
AA HT is also quiet good to snipe models out and suppress infantry, but usually OKW players are using double rekttens if they have fuel problems or are stalling for heavy armor, so careful with that. It is possible, that your adversary can force you to suppress his blob, take your AA out with double rekttens and immediately put skillplanes online, which are poweful on small 1v1 maps.
Most effective strat against OKW is force them to assault you before they are truly ready and wait for a mistaken push. Good example is biting blob on your defensive positions with indirect fire or biting panthers to dive into your lines to get 3476 or t70 and then snare it and put AT overwatch on.
That's pretty much it, hope my suggestion helps.