Cell C SIM not working in the UK after inserted into a different phone???

I am in the UK. My SIM is on prepaid and was working fine until I needed to swop phones. I was receiving phone calls and SMS's and using it on WIFI now I am not able to recieve calls or get necessary sms's in order to may necessary payments in SA. I also need to increase the data on the modem.

I have sent several emails to cell c customer service with no luck. I cannot call as the numbers do not register international numbers?? Please can someone email me to communicate or call me on ********** **********