Android: USSD call not accepting decimal point values only accepts whole numbers?

Question

When i pass the cost value as a decimal, say 13.8, it will remove the '.' and parse it as 138 on the call end. This loop hole is stopping me from making progress. How do i fix this?

String encodedHash = Uri.encode("#");
Uri call = Uri.parse("tel: *151*1*1*555888*"+ cost +"*"+encodedHash);
Intent call_ecocash = new Intent(Intent.ACTION_DIAL, call);
try {
   startActivity(call_ecocash);
    } catch (Exception e) { }