Recently I had changed my Mobile Service Provider by porting my number i.e. your cell no. remains the same even if you change your Mobile Service Provider. After that I recently received my bill, which shows that there were 8 SMS sent to +420720001669, which is a Czech no. I don’t know any one from Czech. So I googled this number & found that Avast has been sending SMS to this no. This is costing me very much. Request to solve this problem at the earliest.
There is no problem, it is as anti-theft is supposed to work.
And you can turn it off in antitheft settings. It is for registering your IMSI, so in case of device lost and internet connection available avast is able to send you SMS with new IMSI, number and location.