[Resolved]  Lava Mobiles — Network issue

For some days ... there has been no network on my Lava Z61pro handset (I use Vodafone 4G ).Today (28/5/21), I removed the sim and then again I inserted the Sim ... now it is showing only "E" in the network, no 4G volte service is available . I thought there was some problem in my Sim, so I changed the Sim ( I used Jio, Airtel), but still same problems are occurring . Kindly fix this with SOFTWARE UPDATE, because your mobile service center services are third ( I can assure you ), they r just good for nothing, they take hours of hours for repair but still in most of the cases they fail to resolve the problem( This problem I faced in a Lava service center in my city Kolkata).